The Knipex 86 03 400 US XL Pliers Wrench is a 16" pliers wrench for plumbers, pipefitters, maintenance techs and installers who work on large union nuts, fittings and bolted connections. This is a pliers wrench designed for gripping, holding, pressing, bending and tightening or loosening large hardware without damaging finished surfaces. Model Number 86 03 400 US opens up to 3-3/8" (85 mm).

The economics are the first reason to buy it. Large fixed open-end wrenches are expensive, and a crew rarely has every size on the truck. This one tool adjusts to any width up to its maximum, inch or metric, and covers the large union joints on water heaters, boilers, pumps and valves that would otherwise take a drawer of single-size wrenches.

The jaws stay parallel through the full range and the faces are smooth. That spreads clamping pressure across the flats instead of concentrating it on the corners, so nuts don't round over. Knipex designed the jaws for gentle installation of quality fittings made of brass, red brass and stainless steel, and the zero-backlash jaw pressure protects sensitive edges on plated and finished parts.

Adjustment is a push-button system with 25 positions, set directly on the workpiece. Press the button, slide the jaws to the nut, release, and the hinge bolt catches securely so the setting doesn't shift while you pull. A lever transmission greater than 10:1 multiplies hand force, so you get a firm hold on a big fitting without squeezing the handles with everything you have.

Once it's sized, the tool works like a ratchet. The jaw action lets you tighten or release a nut with short back-and-forth strokes, which is a big deal when there is only a few degrees of swing room behind a fixture or between pipes.

Knipex forges the pliers wrench from chrome vanadium electric steel and oil-hardens it. The head is chrome-plated, the box joint keeps the jaws aligned under load, and the plastic-coated handles give a secure grip. At 3.2 lbs (1,460 g) it has the mass to feel solid on big hardware. The jaws are slim for the capacity, about 1/2" (12.5 mm) thick at the tip, so they fit into crowded mechanical spaces where a large adjustable wrench head won't.

Who should buy it? Plumbers and HVAC techs setting or servicing equipment with large unions, industrial maintenance crews, and anyone tired of buying oversized wrenches one size at a time. If your work tops out at 2-1/2" hardware, a smaller Knipex pliers wrench is lighter and easier to carry.

The Knipex 86 03 400 US XL Pliers Wrench Pays for Itself in Wrenches You Never Buy

One 16" tool covers large union nuts up to 3-3/8" without marring the fitting.

• Who it's for: Plumbers, pipefitters, HVAC and maintenance techs who handle large unions and finished fittings.
• Why it stands out: Smooth parallel jaws, 25 push-button positions, and a ratcheting action in one German-made tool.
• Worth knowing: At 16" and 3.2 lbs, it's a truck or cart tool, not a pocket tool. For everyday sizes, the 12" Knipex 86 03 300 Pliers Wrench is the one to carry.

• What size fittings does it handle? Any width up to 3-3/8" (85 mm), inch or metric.
• Will it scratch chrome or brass? The jaws are smooth and parallel and designed for gentle installation of brass, red brass and stainless fittings.
• Is it insulated for electrical work? No. It has plastic-coated handles, which are for grip, not electrical protection.