Klein Straight Jaw Quick-Adjust Pump Pliers, 12-in. (D50512BS)

Key Features
Opens to 2-7/8"
The 12" size opens to 2-7/8" (7.3 cm) for big fittings, large locknuts and pipe.
More Leverage
9-1/4" (23.5 cm) handles put more turning force on stuck fittings than a mid-size plier can.
18 Jaw Positions
Eighteen settings and a one-handed quick-adjust button land the jaw on size the first time.
All-Steel Build
Alloy steel with a black oxide and polished finish for strength and long service life.
Overview
The Klein Tools Straight Jaw Quick-Adjust Pump Pliers, 12-Inch (D50512BS) is the 12" size in Klein's straight jaw pump plier family. This is a pump plier designed for large-diameter gripping and turning: big conduit fittings and locknuts, drain and trap connections, pipe and large nuts. It opens to 2-7/8" (7.3 cm) across 18 jaw positions.
Leverage scales with length. At 11-7/8" (30.2 cm) overall with 9-1/4" (23.5 cm) handles, this plier applies noticeably more torque than the 10" size, which is what you want when a fitting has been in place for years. Straight jaws with multiple contact points help put that torque into the work without rounding it off.
The quick-adjust button lets you open or close the jaws one-handed, and the hardened directional teeth hold firm in the direction of the turn while reducing tooth wear. The jaws are 1-1/2" (3.8 cm) long and 5/16" (0.8 cm) wide and thick, keeping a compact, narrow profile for tight spaces even at this size.
It is all alloy steel with a black oxide and polished finish, with bright orange plastic-dipped handles that are easy to spot in a crowded bag. The pliers weigh 1 lb (0.5 kg). They are not insulated.
Who should buy them: plumbers, electricians working with larger conduit, pipe fitters and maintenance crews who need more capacity and leverage than a 10" pump plier offers.
Big Capacity, Straight Bite
Straight jaws with directional teeth grab round and flat stock firmly, even at full opening.
2-7/8" (7.3 cm) jaw capacity
Hardened directional teeth
1-1/2" (3.8 cm) jaw length
Adjust Without Letting Go
The quick-adjust button skips the channel walk, so you can reset the jaw while the other hand holds the work.
Quick-adjust joint
18 jaw positions
Narrow Where It Counts
Even with 12" of reach, the narrow head fits between pipes and behind fixtures.
Compact, narrow design
Jaw width 5/16" (0.8 cm)
Key Specifications
Nominal Size
12"
Overall Length
11-7/8" (30.2 cm)
Jaw Capacity
2-7/8" (7.3 cm)
Jaw Positions
18
Jaw Length
1-1/2" (3.8 cm)
Jaw Type
Straight, hardened directional teeth
Joint
Quick-adjust
Material / Finish
Alloy steel, black oxide and polish
Handle
Plastic dipped, orange, 9-1/4" (23.5 cm)
Insulated
No
Weight
1 lb (0.5 kg)
Built For
Plumbing
Electrical Conduit
Pipe Fitting
Facility Maintenance
HVAC
Tool Nut's Take
Reach for It When the 10-Inch Runs Out
The Klein Tools 12-Inch Straight Jaw Quick-Adjust Pump Pliers (D50512BS) add capacity and leverage without giving up the narrow head.
Who it's for: Plumbers, pipe fitters and electricians working larger fittings and conduit.
Why it stands out: 2-7/8" of capacity, 18 positions and one-handed adjustment in an all-steel plier.
Worth knowing: Not insulated, and at 1 lb it is more plier than you need for small work.
Common Questions
How wide do the Klein D50512BS pliers open? 2-7/8" (7.3 cm) maximum jaw capacity.
How many jaw positions? 18.
Are the handles insulated? No. The handles are plastic dipped for grip, not insulated.