Knipex 87 01 250 Cobra Water Pump Pliers (250mm)

In-Depth Look

The Knipex Cobra 250mm is an adjustable water pump plier for gripping pipes, nuts and fittings. It combines a self-locking jaw with push-button adjustment.

Self-Locking Jaw

The defining feature of the Cobra is its self-locking jaw. As you apply force at the handles, the jaws clamp tighter against the workpiece rather than opening up. This helps reduce rounding on hexagonal fittings and gives a firm grip on round pipe and compression nuts.

Push-Button Adjustment

The push-button adjustment lets you release the jaw, slide it to the width you need and lock it with one hand. Compared with a traditional slip-joint plier, there is less chance of the jaw jumping position under light pressure.

Box Joint

The box-type joint, where one half of the plier passes through the other, gives a stable action compared with a simple open riveted joint. Keep the joint clean and lightly oiled as the maker advises.

Size Range

Knipex makes the Cobra in several lengths. Smaller sizes suit tighter access and smaller compression fittings, while larger sizes take bigger pipework. The 250mm sits in the middle of the range for plumbing and general trade use. This plier is not insulated, so it is not for use on or near live electrical parts.

Summary

The Knipex Cobra 250mm offers a self-locking jaw, push-button adjustment and capacity for nuts up to 46mm and pipes up to 50mm in one tool. It suits plumbers, heating engineers and general builders who need an adjustable plier for pipework and fittings.

How It Compares

The Knipex Cobra 250mm is a self-locking water pump plier made in Germany. It is 250mm long, grips pipe up to 50mm in diameter and flat or nut surfaces up to 46mm. A push button lets you adjust the jaws with one hand, and there are many fixed positions to choose from. Knipex describe the material as chrome vanadium electric steel, oil-tempered, and the handles are plastic coated and non-slip. It uses a box joint design and locks itself onto pipes and nuts. This model is not insulated or VDE rated.

Here is how the Cobra sits against the other tools that grip pipes and nuts.

The Cobra suits plumbing and general workshop use, such as holding a pipe, turning a large nut or gripping a fitting while you turn another. A spanner of the right size is kinder to finished chrome and is the correct tool for critical fittings. The Cobra is not a replacement for the right spanner on gas or other critical connections, so follow the manufacturer’s instructions for the fitting.

For other plumbing hand tools, see the Rothenberger Pipeslice copper pipe cutter and the Monument Masters XV pipe bender.

Common Questions

What is the difference between Cobra pliers and ordinary water pump pliers? Cobra pliers adjust with a push button and lock themselves onto the work, so you can reposition them with one hand. Ordinary slip-joint pliers are adjusted by sliding the jaws between set positions and do not lock by themselves. Both hold round work, but the Cobra’s self-locking grip is the main difference.

Can I use them on nuts and compression fittings? Yes, up to 46mm across the flats. Spanners are kinder to finished chrome, so use the correct size of spanner where a fitting shows. Hold one fitting still while you turn the other, to avoid twisting the pipework.

How do I stop them marking chrome? Wrap the surface in a cloth or masking tape before gripping. The jaws are made to grip, so they leave marks on a bare finish.

What size do I need? This is the 250mm length, which grips pipe up to 50mm and nut surfaces up to 46mm. Other lengths exist, so check the Knipex range if you work with larger or smaller fittings.

Can I use them on gas fittings? They are not a replacement for the correct spanner on gas or other critical fittings. Gas work needs a competent, registered person, and you should follow the manufacturer’s instructions.