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Quick answer from a licensed plumber: Buy the RIDGID RP 251 if nearly all your pressing is 1-1/4 inch and smaller. It is about half the weight of the RP 351 and built for one hand. Buy the RP 351 if you press 1-1/2 or 2 inch copper or bigger mains, since the RP 251 tops out at 1-1/4 inch. They take different jaw series, so the jaws you already own may decide it.
For most service plumbers: the RIDGID RP 251, a 3.6 lb Compact tool that presses up to 1-1/4 inch copper and 1-1/2 inch PEX. Check the RIDGID RP 251 kit on Amazon
The RIDGID RP 351 and RP 251 are both in-line, brushless, Bluetooth press tools with a 360° head. The real split is size. The RP 251 is a Compact Series tool that stops at 1-1/4 inch copper. The RP 351 is a Standard Series tool that presses 1-1/2 and 2 inch, and up to 4 inch with RIDGID’s larger rings and actuators. The two take different jaws, so the choice also decides which jaws and ring actuators you buy for years. For RIDGID against Milwaukee, see RIDGID vs Milwaukee press tools; for every brand together, see the best press tools. I run RIDGID and Milwaukee tools on my own jobs; every spec below comes from RIDGID’s documents.
RP 351 vs RP 251 Side by Side
| RP 251 (Compact) | RP 351 (Standard) | |
|---|---|---|
| Copper / stainless | 1/2 to 1-1/4 in. | 1/2 to 4 in. copper (XL-C rings and V2 actuator for 2-1/2 to 4 in.) |
| PEX | 1/2 to 1-1/2 in. | 1/2 to 2 in. |
| Carbon steel | 1/2 to 1 in. | 1/2 to 4 in. (booster for 2-1/2 to 4 in.) |
| Ram force | 5,400 lb (24 kN) | 7,200 lb (32 kN) |
| Stroke | 1.2 in. | 1.57 in. |
| Battery | 12V | 18V |
| Presses per charge | Up to 140 | More than 325 (3/4 in. Type L) |
| Cycle time | ~5 sec | 4.5 sec |
| Weight, tool only | 3.6 lb | 6.8 lb (2024 catalog); 7.1 lb (2020 sheet); 7.83 lb (manual) |
| Length | 13 in. | 15.6 in. |
| Motor rating | Over 60,000 press cycles | Over 100,000 press cycles |
| Jaw series | Compact only | Standard only |
| Linked kit | 78148, jaws 1/2 to 1-1/4 in. | 67178, jaws 1/2 to 2 in. |
From RIDGID’s catalog sheets, 2024 pressing catalog and operator’s manuals, read on October 1, 2026. Where RIDGID documents give different numbers, each is shown. Every linked listing was sold by Amazon.com and in stock that day.
Which One Should You Buy?
Start with the biggest pipe you press
If your work is water services, fixtures, water heaters and hydronic loops at 1-1/4 inch and under, the RP 251 covers it and weighs about half as much. If you press 1-1/2 or 2 inch copper on mains, risers or commercial jobs, the RP 251 cannot do it, and the RP 351 is the one that can. Plumber’s note: count the 1-1/2 and 2 inch joints you pressed last year. If the answer is “a few,” a second tool or a rental may beat carrying the bigger tool every day.
Your jaws decide more than the tool does
RIDGID’s manuals say Standard and Compact attachments are not interchangeable. If you already own Standard Series jaws from an RP 340 or RP 330, the RP 351 keeps them working. If you are starting clean, add the jaws you need to the cost of the tool. Fitting systems matter too: RIDGID says to use its tools and attachments only when the fitting maker specifies them for that system. Our MegaPress vs ProPress guide covers the steel and copper systems.
Weight and one-handed reach
RIDGID lists the RP 251 at 3.6 lb for the tool alone and 6.7 lb with the battery and a 1/2 inch copper jaw, with a forward trigger built for one hand. The RP 351 is 6.8 to 7.83 lb for the tool alone, depending on which RIDGID document you read. Overhead in a ceiling or under a cabinet, that difference adds up over a day. Both heads turn 360°, and both have LED lighting.
Battery and run time
The RP 251 runs on RIDGID’s 12V battery and is rated for up to 140 presses per charge. The RP 351 runs on 18V and is rated for more than 325 presses per charge on 3/4 inch Type L copper, about 2.3 times as many (our arithmetic). The RP 351 can also run from RIDGID’s RPA 120/220 AC power adapter, per its manual. If you already run RIDGID 18V tools, the batteries may be a deciding point.
RIDGID RP 251 Compact Press Tool (Kit 78148)
Compact Series · 1/2 to 1-1/4 in. copper and stainless, 1/2 to 1-1/2 in. PEX, 1/2 to 1 in. carbon steel · 5,400 lb (24 kN) ram force · 12V battery · up to 140 presses per charge · 3.6 lb tool only · in-line with forward trigger · 360° head · Bluetooth (RIDGID Link app)
RIDGID calls the RP 251 the newest tool in its Compact Press Tool family. Its catalog sheet lists 1/2 to 1-1/4 inch on copper and stainless steel, 1/2 to 1-1/2 inch on PEX, 1/2 to 1 inch on carbon steel and 1/4 to 1-3/8 inch on refrigeration copper. The manual gives 5,400 lb (24 kN) of ram force and a 1.2 inch stroke. It runs on a 12V battery, and RIDGID says it completes up to 140 presses per charge. The tool alone is 3.6 lb on the catalog sheet, and 6.7 lb with the battery and a 1/2 inch copper jaw.
The point of the RP 251 is one hand. RIDGID describes an in-line body with a forward-positioned trigger and a SlimGrip handle for one-handed use, plus a 360° head swivel and an LED light ring. Its brushless motor is rated for over 60,000 press cycles with no scheduled maintenance. RIDGID’s US catalog sheet and its pressing catalog both list a cycle time of about 5 seconds. The linked kit (78148) comes with ProPress jaws for 1/2 to 1-1/4 inch, per the listing. If you only press 1/2 to 1 inch, the RP 251 kit 78158 has jaws for 1/2 to 1 inch.
- One-handed in-line design with a forward trigger, per RIDGID
- 3.6 lb tool only, about half the RP 351 (our arithmetic)
- Presses up to 1-1/2 in. PEX and 1-1/4 in. copper and stainless
- Bluetooth press counts, tool locking and service info in the RIDGID Link app
- Tops out at 1-1/4 in. copper; no 1-1/2 or 2 in. copper
- Takes Compact Series jaws only; Standard Series jaws do not fit
- 140 presses per charge on the 12V battery, per RIDGID
- Rated for 60,000 press cycles vs over 100,000 on the RP 351
Verdict: The press tool for service work and remodels where nearly every joint is 1-1/4 inch or smaller.
RIDGID RP 351 Standard Press Tool (Kit 67178)
Standard Series · 1/2 to 4 in. copper and carbon steel (2-1/2 to 4 in. copper uses XL-C rings and the V2 actuator; carbon steel at that size needs the Press Booster), 1/2 to 2 in. PEX · 7,200 lb (32 kN) ram force · 18V battery · more than 325 presses per charge · 4.5 second cycle · in-line body · 360° head · Bluetooth
The RP 351 is RIDGID’s in-line Standard Series tool; the RP 350 is the same tool in a pistol body. The catalog sheet lists 1/2 to 4 inch copper, 1/2 to 4 inch carbon steel and 1/2 to 2 inch PEX, with a note that a Press Booster is needed for 2-1/2 to 4 inch carbon steel. RIDGID’s pressing catalog lists ProPress XL-C rings for 2-1/2 to 4 inch copper, used with its V2 actuator. The manual lists 7,200 lb (32 kN) of ram force, a 1.57 inch stroke and an 18V battery. RIDGID gives a 4.5 second crimp cycle and more than 325 presses per charge, based on 3/4 inch fittings on Type L copper.
RIDGID says the RP 350 and RP 351 are the only press tools compatible with all RIDGID Standard Series jaws, rings, actuators and attachments. The brushless motor is rated for over 100,000 press cycles with no scheduled maintenance. The weight is listed three ways: 6.8 lb for the tool alone in RIDGID’s 2024 pressing catalog, 7.1 lb on the 2020 catalog sheet and 7.83 lb with no battery or attachment in the manual. The linked kit (67178) includes a battery, charger, 1/2 to 2 inch press jaws and a carrying case, per the listing. If you prefer a pistol grip, the RP 350 kit 67063 is the pistol version; RIDGID’s catalog sheet lists that kit with no jaws.
- Presses 1-1/2 and 2 in. copper with standard jaws, up to 4 in. with RIDGID’s rings and actuators
- 7,200 lb (32 kN) ram force, 1/3 more than the RP 251 (our arithmetic)
- More than 325 presses per charge on 3/4 in. Type L, per RIDGID
- Takes every RIDGID Standard Series jaw, ring and actuator
- About twice the weight of the RP 251 (6.8 to 7.83 lb vs 3.6 lb; our arithmetic)
- Longer: 15.6 in. vs 13 in. for the RP 251 (catalog sheets)
- Standard Series jaws only; your Compact jaws will not fit
- Larger sizes need rings and actuators or the booster, bought separately
Verdict: The press tool to buy if you press 1-1/2 inch and 2 inch copper or plan on bigger mains.
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Before You Buy
- List your largest pipe size. Over 1-1/4 inch copper means the RP 351.
- Check the jaws you own. Standard jaws fit only Standard tools; Compact jaws fit only Compact tools.
- Read the kit contents. The 78148 RP 251 kit includes 1/2 to 1-1/4 inch ProPress jaws, the 78158 kit 1/2 to 1 inch, and the 67178 RP 351 kit 1/2 to 2 inch, per the listings.
- Match the fitting system. Use the jaw or ring profile the fitting maker names. See NIBCO press vs Viega ProPress.
- Check the temperature range. Both manuals list 15°F to 122°F, but RIDGID’s 2024 pressing catalog lists the RP 251 at 15°F to 104°F. The RP 350/351 manual says the tool will not run outside its range, so keep tools and batteries in a conditioned space on cold days.
Pressing Tips From the Manuals
Both tools have a Normal Mode, where one press of the switch runs the cycle, and a Control Mode, where the first press closes the jaw on the fitting so you can adjust it before the second press runs the cycle. The RP 251 manual says that once the tool locks on, releasing the switch will not stop it, which keeps every press consistent. Both tools have colored status lights, and each manual lists what every light means. Mark the insertion depth before you press; our insertion depth guide shows how. Plumber’s note: a pressed joint is only as good as the cut and the depth mark. Square cuts, deburred ends and a visible mark at the fitting shoulder matter more than which tool you carry.
FAQ
Can I use RP 351 jaws on the RP 251?
No. RIDGID sells press attachments in two series, Standard and Compact, and its manuals say they are not interchangeable. Standard Series attachments work only on Standard tools such as the RP 350 and RP 351. Compact Series attachments work only on Compact tools such as the RP 251, RP 240 and RP 241. One exception: RIDGID’s pressing catalog says its press rings can be used with all RIDGID press tools, Standard and Compact. The actuator that drives the ring is series-specific: V1 and V2 for Standard tools, C1 for Compact tools.
Can the RP 251 press 2 inch copper?
No. RIDGID lists the RP 251 at 1/2 to 1-1/4 inch on copper and stainless steel. For 1-1/2 and 2 inch copper you need a Standard tool like the RP 351, which RIDGID lists at 1/2 to 4 inch copper. Above 2 inch, RIDGID’s catalog lists ProPress XL-C rings with its V2 actuator.
What is the difference between the RP 350 and RP 351?
The body. RIDGID’s manual lists the RP 350 as the pistol press tool and the RP 351 as the in-line press tool, with the same 7,200 lb ram force, 1.57 inch stroke, 18V power and Standard Series attachments. Pick the shape that fits how you hold the tool overhead and in tight bays.
How many presses do I get per battery?
RIDGID lists up to 140 presses per charge for the RP 251 on its 12V battery, and more than 325 for the RP 350 and RP 351 on 18V, based on 3/4 inch fittings on Type L copper. Pipe size, material and fitting type change the number.
Do these tools need scheduled maintenance?
RIDGID’s catalog sheets list no scheduled maintenance for either tool, with motors rated for over 60,000 press cycles (RP 251) and over 100,000 (RP 351). RIDGID’s 2024 pressing catalog lists the RP 251 service interval as 60,000 cycles, and its RIDGID Link app shows press cycles and service interval. The RP 351 manual says the app monitors tool cycles and the status lights show when maintenance is required.
Why Trust Plumbing Picks
Plumbing Picks is written by a licensed Georgia journeyman plumber who uses RIDGID and Milwaukee tools on jobs. Every spec here comes only from the RIDGID documents listed below or from the Amazon listings we link. On October 1, 2026, every linked listing was sold by Amazon.com and in stock. If you buy through a link we may earn a commission at no extra cost to you. Nobody pays to be included here. More on who writes this and how we pick.
Sources
- RIDGID: Pressing Product Catalog (rings, actuators, Press Booster), RIDGID: RP 350 & RP 351 catalog sheet R-20-I, RP 350/RP 351 operator’s manual, RP 351 product page
- RIDGID: RP 251 catalog sheet R-24-G, RP 251 product page, RP 251 operator’s manual
- Amazon listings for the RIDGID 67178 RP 351 kit, the 78148 and 78158 RP 251 kits and the 67063 RP 350 kit (linked above)
Bottom Line
The RP 251 and RP 351 share an in-line body, a 360° head and Bluetooth; they split on size, force and jaws. The RP 251 is the lighter, one-handed tool for 1/2 to 1-1/4 inch work. The RP 351 adds 2 inch copper with standard jaws, up to 4 inch with rings and an actuator, more presses per charge and the full Standard Series jaw line. Pick by the biggest pipe you press and the jaws you already own.