Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.
Estwing E3-16C: a 16 oz curved claw forged in one piece
You want one hammer in the truck or the house for pipe straps, blocking, trim and pulling nails, and you’d rather it never loosen at the head.
Skip it if
You frame walls or nail 2x lumber all day. A 19 to 20 oz head like the EB-19SM or E3-20S drives 16d nails in fewer swings.
The Estwing E3-16C is my top pick because it’s the simplest good hammer you can buy. Estwing forges the head and handle in one piece of steel, then molds its Shock Reduction Grip onto the handle.
One piece matters on a hammer that gets thrown in a bucket and used for years. There’s no separate handle to work loose from the head, and no wood to dry out.
The head is 16 oz, and the hammer is 13 in. long, per Estwing’s options table. That’s the shortest hammer on this page and a size that’s easier to swing inside a vanity cabinet or between joists.
The claw is curved. Estwing’s listing says the curve adds torque when you pull and pry nails, which is the job a curved claw is shaped for.
In plumbing work, a 16 oz hammer covers most of what you’ll nail: pipe straps and hangers, blocking for a wall-hung sink, nail plates over pipe in studs and the odd trim board you had to pull.
The face is smooth, so it leaves fewer marks on trim and finished surfaces than a milled face. The trade-off is that a smooth face can glance off a nail head on a fast, hard swing.
Estwing’s listing says the molded grip cuts impact vibration by 70%. The listing also says Estwing makes it in Rockford, Illinois, from American steel.
Wirecutter also picks the E3-16C, which is part of why it made my shortlist. I picked it on Estwing’s own specs: one piece, a curved claw and a size you can carry everywhere.
Read Estwing’s rules before you use any nail hammer. Estwing says these hammers are made to drive and pull common unhardened nails only, and you should wear safety goggles.
Estwing’s warranty covers failure in normal use. It isn’t a lifetime warranty, and it excludes misuse like striking chisels or other hardened tools.
My call: if you buy one claw hammer, buy this one.
Head weight and length for each hammer
A heavier head drives a nail in fewer swings. A longer handle adds speed at the head. Here’s what each maker lists.
Pick
Head weight
Overall length
Handle
Total weight
Estwing E3-16C
16 oz
13 in.
Steel, one piece
Not listed
Estwing E3-20S
20 oz
13.75 in.
Steel, one piece
Not listed
Klein H80718
18 oz
14.8 in.
Fiberglass, 13 in.
1.9 lb
Klein H80920S
20 oz
16 in.
Steel core, 15 in.
1.86 lb
Estwing EB-19SM
19 oz
15.5 in.
Steel, one piece
Not listed
Vaughan DDT16P
16 oz, titanium
17 in. handle
Hickory
Not listed
Listed length of each hammer, as a share of the longest. Vaughan lists the handle length; the others list overall length.
From Estwing’s, Klein’s and Marshalltown’s (Vaughan’s) product pages, read Oct 19, 2026.
Head weight is the number printed on the hammer, like 16 oz or 20 oz. Klein also lists the total weight, so you can see the handle adds about 12 oz on the H80718.
Length works with weight. The Vaughan’s 16 oz head sits on a 17 in. handle, and Vaughan says its titanium head has the same strength as a steel hammer. In a tight cabinet, a shorter hammer is easier to swing.
Estwing E3-20S: a 20 oz rip claw for blocking and demo
Straight claw pulls nails with less leverage than a curve
Short for a 20 oz head, 13.75 in.
No magnetic nail starter
E3-20S20 oz head13.75 in. longRip clawSmooth face
Buy it if
You nail 2x blocking, rip out old framing to reroute pipe, or pry boards apart, and you want the same one-piece build as the E3-16C.
Skip it if
You mostly pull nails. The curved claw on the E3-16C gives more leverage on a nail.
The Estwing E3-20S is the same one-piece Estwing build with more head and a straighter claw. Estwing forges it from solid American steel, polishes it and molds on the Shock Reduction Grip.
The head weighs 20 oz, and the hammer is 13.75 in. long, per Estwing’s options table. That ties it with the Klein H80920S for the heaviest head on this page.
Estwing calls the claw a rip claw. Its listing says that shape is for pulling nails, prying boards, demolition work and splitting wood.
A rip claw is flatter than a curved claw. You can drive it between two boards and lever them apart, or swing it into drywall or old lath during demo.
In plumbing work, that’s the hammer for opening up old framing. When a drain has to move, old blocking is often in the way, and a rip claw pries it out.
The extra weight also helps when you nail 2x blocking between studs for a grab bar or a wall-hung sink. A heavier head drives 16d nails in fewer swings.
Estwing’s listing says the longer handle gives more striking power. At 13.75 in., it’s longer than the 16 oz E3-16C but shorter than the Klein and Vaughan framers.
The face is smooth, like the E3-16C. Estwing makes the same rip hammer in 12 and 16 oz too, so the 20 oz is the heavy one in the line.
Estwing says nail hammers are for driving and pulling common unhardened nails only. Estwing lists pulling hardened nails, screws or nail sets as misuse, so keep the claw on common nails.
Estwing lists a dented handle neck from over-striking as wear, not a warranty claim. Aim for the nail, not the board edge.
My call: if you do more demo than trim, get this one.
Curved claw or straight claw: which one you need
The claw decides what the hammer does after the nail is in. Here’s each pick’s claw, per its maker.
You pull more nails than you pry. The curve rolls on the work and lifts the nail, which is the torque Estwing describes.
Pick a straight or rip claw if
You pry boards, split old framing or tear out wall material. Estwing lists all three for its rip claw.
Pick a side puller if
You pull nails where there’s no room to rock the hammer back. Klein’s dual side pullers and Vaughan’s SideWinder puller are both sold for extra leverage.
Don’t use any claw on
Hardened nails, screws or nail sets. Estwing lists pulling them as misuse that can cause injury.
Klein H80718: an 18 oz straight claw on a fiberglass handle
Best for a fiberglass handle
Klein H80718
Klein Tools H80718 straight-claw hammer, 18 oz, fiberglass
H8071818 oz head14.8 in. longFiberglass1.9 lb total
Buy it if
You want a middle-weight hammer with a softer feel than solid steel, and you work around cable staples when you run pipe through framing.
Skip it if
You want the biggest face for fewer missed hits. The Klein H80920S has a 1.6 in. face.
The Klein H80718 is the pick for a fiberglass handle. Klein says the high-strength fiberglass core gives maximum shock absorption, and the grip is non-slip.
It’s the only fiberglass handle on this page. The three Estwings are solid steel, the H80920S has a steel core and the Vaughan is hickory.
The head is 18 oz forged steel with a smooth face, which Klein says is for reduced marring. Klein lists the head at 1.13 lb, the face at 1.1 in. across and the total weight at 1.9 lb.
The claw is straight, and Klein says it’s engineered for removing NM-B (Romex) staples. Klein sells it as an electrician’s hammer, but it’s a solid general purpose hammer too, in Klein’s own words.
That staple feature matters when you run pipe through a wall that already has wiring. Moving cable is the electrician’s call. If you’re cleared to pull a staple, this claw is shaped for it, per Klein.
It’s 14.8 in. overall with a 13 in. handle, per Klein’s spec sheet. That’s longer than either 16 or 20 oz Estwing, which adds a little speed to each swing.
There’s a hang hole in the handle for tethering or hanging storage, Klein says. On a ladder or a scaffold, a tethered hammer can’t fall on someone below.
Klein’s warnings are worth reading: wear eye protection, never use it on or near live circuits, and don’t strike hammer faces together. Klein also notes it’s not insulated.
The face is the smallest on this page. A 1.1 in. face asks for more accuracy than Klein’s own 1.6 in. squared face on the H80920S.
Klein’s product page doesn’t list a warranty term, so I can’t compare that with Estwing’s.
Its spec score is the lowest here, 7.2, for two reasons: Klein lists no warranty term and no magnetic nail starter. The fiberglass handle and staple-shaped claw still earn it the pick for wiring-heavy walls.
My call: if you want a lighter-feeling hammer that’s still 18 oz, get this one.
Which hammer fits which plumbing job
These are common nailing and prying jobs on a plumbing rough-in or repair, matched to the hammer whose maker describes that kind of work.
Pipe straps and hangers
Estwing E3-16C. A 16 oz head and 13 in. length fit between joists and in cabinets.
Blocking for a sink or grab bar
Estwing E3-20S or EB-19SM. A 19 to 20 oz head drives 2x nails in fewer swings.
Nailing overhead or one-handed
Klein H80920S or Vaughan DDT16P. Both makers list a magnetic nail starter.
Opening old framing to reroute a drain
Estwing E3-20S. Estwing lists prying boards and demolition for its rip claw.
Working near stapled cable
Klein H80718. Klein shaped its claw to pull NM-B staples.
Chisels, punches and hardened pins
Not a claw hammer job. Estwing lists striking chisels and hardened objects as misuse.
Pick
Handle material
Grip
Tether or hang hole
Estwing E3-16C
Steel, forged with head
Molded Shock Reduction Grip
Not listed
Estwing E3-20S
Steel, forged with head
Molded Shock Reduction Grip
Not listed
Klein H80718
Fiberglass
Non-slip grip
Hang hole
Klein H80920S
Full steel core
Cushion grips
Not listed
Estwing EB-19SM
Steel, forged with head
Molded Shock Reduction Grip
Not listed
Vaughan DDT16P
American hickory
Overstrike guard on handle
Not listed
Handle and grip details as each maker lists them, read Oct 19, 2026. “Not listed” means the maker doesn’t name the feature.
Klein H80920S: a 20 oz framer with a magnet
Best for one-handed nail starts
Klein H80920S
Klein Tools H80920S smooth face steel claw hammer, 20 oz
H80920S20 oz head16 in. long1.6 in. face1.86 lb total
Buy it if
You nail overhead or at arm’s length, where a magnet that holds the nail lets you start it with one hand and keep the other on the ladder.
Skip it if
You want a milled face that grips the nail head. The Estwing EB-19SM has one.
The Klein H80920S is a 20 oz framing hammer with two features the Estwings here don’t have: a magnetic nail starter and an extra-large squared strike face.
Klein says the squared face reduces missed hits and helps drive nails in tight spaces. It lists the face at 1.6 in. across, the largest published face on this page.
The magnet holds a nail in the head so you can set it with one hand, Klein says. That’s the job for overhead strapping or nailing at full reach.
Klein also gives it dual side nail pullers. Klein says they add leverage and help pull nails in tight spaces, where you can’t rock the hammer back on the claw.
Under a floor or between joists, that side puller helps get a bent nail out of the way of a new pipe run.
The handle has a full steel core with cushion grips, per Klein. Klein lists the application as a framing claw hammer.
It’s 16 in. long with a 15 in. handle, and it weighs 1.86 lb in total, per Klein’s spec sheet. The head is 1.25 lb, which is the 20 oz in its name.
Klein’s spec sheet lists an ASME B107.400-2018 standard. The finish is black powder coat, and the handle is black and orange.
The face is smooth, which Klein says reduces damage to materials. That makes it a better fit than a milled face when the board will stay exposed.
Klein’s warnings: wear eye protection, never use it near live circuits, don’t strike hammer faces together, and remember it’s not insulated.
On the spec score it lands at 8.0. The magnet and side pullers earn full marks, while the 16 in. length and the missing warranty term cost it points against the shorter Estwings. For overhead strapping, the magnet matters more than those two.
My call: if you nail one-handed a lot, get this one.
When to retire a hammer, and what makers warn about
Hammers wear out. Estwing prints a discard list under the nail hammer safety standard, and Klein prints its own warnings.
Sign
What it means
Source
Chips or dents on the face
Discard the hammer
Estwing warranty page
Mushroomed face
Discard the hammer
Estwing warranty page
Crack in the claw
Discard the hammer
Estwing warranty page
Dents in the handle
Discard the hammer
Estwing warranty page
Milled face worn smooth
Normal wear, not a defect
Estwing warranty page
Struck a chisel or another hammer
Misuse; not covered
Estwing and Klein
Estwing says it can’t repair, re-grip or refurbish a used striking tool, in line with the ANSI nail hammer safety standard, B173.1. Estwing warns that misuse can cause eye or bodily injury, which is why the discard list is short and strict.
Wear safety glasses every time. Estwing says bystanders should too, and Klein’s first warning on both of its hammers is approved eye protection.
Estwing EB-19SM: a 19 oz milled face framer with a magnet
Estwing lists a worn milled face as wear, not a defect
Long for tight cabinets
EB-19SM19 oz head15.5 in. longMilled faceRip claw
Buy it if
You nail framing lumber, like blocking, backing and sleepers, where a face that grips the nail matters more than a clean finish.
Skip it if
You nail trim or anything that stays visible. A milled face leaves a waffle print, so use a smooth face like the E3-16C.
The Estwing EB-19SM is Estwing’s Ultra Series framer. Estwing says the slimmer profile makes it lighter and more aerodynamic than other hammers, with the same one-piece forging and no welds or joints.
The SM version has a milled face, per Estwing’s options table. Vaughan describes a milled face as one that grips nail heads and reduces slippage, so it’s less likely to slide off on a hard swing.
That’s the reason framers use milled faces. The catch is the mark it leaves: a milled face prints its pattern into the wood if you miss the nail or set it flush.
The head is 19 oz, and the hammer is 15.5 in. long, per Estwing’s options table. That length is 2.5 in. more than the E3-16C, which adds speed at the head.
Estwing’s listing adds a magnetic nail starter for one-handed nailing. It also says the rip claw is for pulling nails, prying and demolition.
In plumbing rough-in, a milled framer is the hammer for structural nailing. Blocking for a shower valve and backing for a wall-hung lav both take big nails into framing that gets covered.
The grip is Estwing’s patented Shock Reduction Grip, in black. Estwing’s listing says it reduces vibration by 70%, the same claim as its other steel hammers.
Estwing makes the Ultra in 15 and 19 oz, with smooth or milled faces. If you want the same hammer for exposed work, the EB-19S is the smooth face version.
Estwing’s warranty page lists a worn-down milled face as normal wear. Expect the pattern to dull with heavy use. Estwing doesn’t replace a hammer for that.
Like every Estwing nail hammer, it’s for common unhardened nails only. Wear safety goggles.
My call: if you nail framing more than trim, get this one.
Smooth face or milled face: which one to pick
The face is the part that hits the nail. Here’s each pick’s face, and what each maker says about it.
Pick
Face
Face size
Magnetic starter
Estwing E3-16C
Smooth
Not listed
No
Estwing E3-20S
Smooth
Not listed
No
Klein H80718
Smooth, for reduced marring
1.1 in.
No
Klein H80920S
Smooth, extra-large squared
1.6 in.
Yes
Estwing EB-19SM
Milled
Not listed
Yes
Vaughan DDT16P
Smooth (milled sold as VN07180)
Not listed
Yes, NaiLoc
Listed head weight, as a share of the heaviest. Vaughan says its titanium head swings faster with less effort and matches a steel hammer’s strength.
Use a smooth face for anything that stays visible: trim, cabinets and finished panels. Use a milled face for framing that gets covered, where grip on the nail matters more than marks.
Only Klein lists face size. Its squared H80920S face is 1.6 in. across, about half again the 1.1 in. face on the H80718.
Vaughan DDT16P: titanium on a hickory handle
Best for a light head on a long handle
Vaughan DDT16P
Vaughan Dalluge DDT16P titanium hammer, 16 oz, smooth face
Vaughan doesn’t list a warranty term on the product page
DDT16P16 oz titanium17 in. hickorySmooth faceSide puller
Buy it if
You nail a lot overhead or all day and want a lighter hammer that still drives framing nails, per Vaughan’s description.
Skip it if
You work in cabinets and crawl spaces. The 13 in. Estwing E3-16C fits where a 17 in. handle won’t.
The Vaughan DDT16P is the titanium pick. Vaughan says its precision-cast, one-piece titanium head gives faster swings with less effort, with the same strength as a traditional steel hammer.
That’s a maker claim, and it’s the whole reason to buy titanium. A 16 oz head is lighter than the 19 and 20 oz steel framers here, and the 17 in. handle gives it speed at the end of the swing.
Vaughan lists it for framing and structural work, demolition and installing shingles and other roofing. It’s a framer, not a trim hammer.
The handle is American hickory. Vaughan says it absorbs shock and has less recoil, and an overstrike guard protects it from missed or hard strikes.
Vaughan adds two features to the head. The NaiLoc magnetic nail holder lets you start nails one-handed with more reach. The SideWinder nail puller adds leverage when you pull nails, Vaughan says.
Overhead is where a light hammer pays off. Strapping pipe to the bottom of joists or nailing hangers in a ceiling is a lot of swings with your arm above your shoulder.
Vaughan makes this 16 oz hammer with a smooth face, part VN07182, or a milled face, part VN07180. This listing is the smooth face.
The titanium head is corrosion-resistant, per Vaughan. That’s useful for a hammer that rides in a damp truck or lives in a crawl space bucket.
Marshalltown sells the Vaughan line on its own site, and its site showed a 4-week wait on Oct 19. The Amazon listing was new and in stock when re-checked Oct 22, 2026, 6:16 PM EDT.
Vaughan’s product page doesn’t list a warranty term. A wood handle also needs care: don’t leave it soaking in a wet bucket.
My call: if you swing a hammer overhead most of the day, get this one.
The six hammers side by side
Pick
Spec score
Best for
Head
Length
Claw
Face
Estwing E3-16C
9.2
Most plumbing and home jobs
16 oz steel
13 in.
Curved
Smooth
Estwing E3-20S
8.6
Blocking, demo, prying
20 oz steel
13.75 in.
Rip
Smooth
Klein H80718
7.2
Fiberglass handle
18 oz steel
14.8 in.
Straight
Smooth, 1.1 in.
Klein H80920S
8.0
One-handed nail starts
20 oz steel
16 in.
Straight, side pullers
Smooth, 1.6 in.
Estwing EB-19SM
9.0
Driving framing nails
19 oz steel
15.5 in.
Rip
Milled
Vaughan DDT16P
7.8
Light head, long handle
16 oz titanium
17 in. handle
SideWinder puller
Smooth
From Estwing’s, Klein’s and Marshalltown’s product pages, read Oct 19, 2026. All six were new and in stock when re-checked Oct 22, 2026, 6:16 PM EDT.
How to choose a claw hammer
If you…
Get
Why
Want one hammer for everything
Estwing E3-16C
16 oz, curved claw, one piece
Nail blocking and do demo
Estwing E3-20S
20 oz, rip claw
Want a softer-feeling handle
Klein H80718
Fiberglass core
Nail overhead one-handed
Klein H80920S
Magnet, 1.6 in. squared face
Frame a lot
Estwing EB-19SM
19 oz, milled face, 15.5 in.
Swing all day overhead
Vaughan DDT16P
Titanium head, 17 in. handle
Start with head weight. A 16 oz hammer handles straps, hangers and trim. A 19 to 20 oz head is for framing nails. Heavier isn’t better in a cabinet, where you can’t take a full swing.
Then pick the claw and face. Curved claws pull nails; rip claws pry. Smooth faces leave fewer marks; milled faces grip. If you need to break concrete or drill block, see our rotary hammer guide instead.
Questions people ask
What is the best quality claw hammer?
For most people, the Estwing E3-16C. Estwing forges the head and handle in one piece of American steel, so there’s no joint to loosen.
What is the best hammer on the market?
It depends on the job. The Estwing E3-16C for general work, the Estwing EB-19SM for framing, and the Vaughan DDT16P if you want a titanium head.
What is the best 20 oz claw hammer?
The Estwing E3-20S for one-piece steel and a rip claw, or the Klein H80920S if you want a magnetic nail starter and a 1.6 in. squared face.
What size claw hammer should I get?
16 oz for general work, straps and trim. 19 to 20 oz for framing nails. The Estwing E3-16C is 16 oz and 13 in. long.
Is a curved or straight claw better?
A curved claw pulls nails with more leverage, per Estwing. A straight or rip claw is better for prying boards and demo.
Should I get a smooth or milled face?
Smooth for work that stays visible, since it marks less. Milled for framing, since it grips the nail head but leaves a pattern in the wood.
Is a titanium hammer worth it?
If you swing a lot, maybe. Vaughan says its titanium head gives faster swings with less effort and the same strength as steel. It’s a 16 oz head on a 17 in. handle.
Can I hit a chisel with a claw hammer?
No. Estwing says nail hammers are for common unhardened nails only, and lists striking chisels and other hardened tools as misuse. See our ball-peen hammer guide.
When should I throw a hammer away?
Estwing says to discard it if the face is chipped, dented or mushroomed, the claw is cracked, or the handle is dented.
How I picked these
Why trust me
I’m Isaac Daniels, a licensed journeyman plumber in Georgia (license #JP507711). These picks come from what Estwing, Klein Tools and Vaughan publish, read the same day, sorted by the job you’d use each hammer for.
How I pick
One pick per job: general work, demo, a fiberglass handle, one-handed nailing, framing and overhead work.
Facts from the makers’ product pages, spec sheets and warranty pages, plus the Amazon listing text. Anything not stated is marked “Not listed”.
Genuine branded tools, new, in stock and sold one at a time, re-checked Oct 22, 2026, 6:16 PM EDT. Prices read from Amazon with the time shown, never typed in.
One spec score for all six hammers, worked out below. Head weight is left out of it, since each weight suits a different job.
The spec score, check by check
Each check scores 0 to 10 and counts one fifth. It rewards shock control, a magnetic nail starter, a claw that pulls with leverage, a length that fits under a sink, and a published warranty. It’s my score from the makers’ figures, not a customer rating or a swing test.
Head weight isn’t a check, because 16 oz and 20 oz suit different jobs. The Estwing E3-16C leads because it’s short and pulls with a curved claw; the Klein H80718 scores lowest because Klein lists no warranty term and no nail starter.
Check (weight)
How it’s scored
Shock control (⅕)
10 for a one-piece forged steel hammer with a shock grip and a published vibration figure; 9 for a shock-absorbing fiberglass or steel core with a cushion grip; 8 for a wood handle with an overstrike guard
Nail starting (⅕)
10 for a magnetic nail starter; 6 for none
Nail pulling (⅕)
10 for a curved claw, or a straight claw with added side pullers; 8 for a straight claw with a shaped staple puller; 7 for a plain rip claw
Fits tight spaces (⅕)
Overall length, because cabinets and joist bays are tight: 10 under 14 in.; 8 for 14 to 15.9 in.; 6 for 16 in. or more
Warranty (⅕)
10 for a published warranty that covers normal use; 5 when the maker’s page lists no term
Total
Average of the checks, to one decimal
Pick
Shock control
Nail starting
Nail pulling
Fits tight spaces
Warranty
Score
Estwing E3-16C
10
6
10
10
10
9.2
Estwing E3-20S
10
6
7
10
10
8.6
Klein H80718
9
6
8
8
5
7.2
Klein H80920S
9
10
10
6
5
8.0
Estwing EB-19SM
10
10
7
8
10
9.0
Vaughan DDT16P
8
10
10
6
5
7.8
Sources
Estwing E3-16C Claw Hammer product page and options table: estwing.com, read Oct 19, 2026.
Estwing E3-20S Rip Hammer product page and options table: estwing.com, read Oct 19, 2026.
Estwing EB-19SM Ultra Series Hammer product page and options table: estwing.com, read Oct 19, 2026.
Estwing warranty and safety page (general product warranty, discard list, ANSI/HTI B173.1): estwing.com, read Oct 19, 2026.
Klein Tools H80718 Straight-Claw Hammer product page, specifications and warnings: kleintools.com, read Oct 19, 2026.
Klein Tools H80920S Smooth Face Steel Claw Hammer product page, specifications and warnings: kleintools.com, read Oct 19, 2026.
Vaughan Dalluge Series 16 oz Titanium Hammers (VN07182 and VN07180) product page: marshalltown.com, read Oct 19, 2026.
Amazon listing text for each pick, read Oct 19, 2026.
Google results for “best claw hammer” (top results, including Wirecutter and Pro Tool Reviews, and People also ask), read Oct 19, 2026.
CPSC recalls: searched for claw hammer, hammer, Estwing, Vaughan and Stiletto on Oct 19, 2026. No claw hammer recalls found.
Amazon product data through Amazon’s Creators API (prices, sellers, stock, photos), refreshed daily; each price shows the time it was read.
Amazon Creators API, B00002N5NA, B0000224VC, B09LHTKKMY, B0FH3BGX7P, B00FF2TK68 and B001IWOLDG: New, in-stock offers and image URLs, re-read Oct 22, 2026, 6:16 PM EDT.
U.S. Consumer Product Safety Commission recall search for Estwing, Klein Tools and Vaughan (saferproducts.gov), Oct 22, 2026, 6:16 PM EDT: none for hammers (Klein’s listed recalls cover power stations, voltage testers and clamp meters).