Pull coiled tubing through these straighteners to make it smooth and level. They have acetal roller wheels that press your tubing into shape without marring the finish. Unlike pliers, which create kinks and bends that can restrict flow, these straighteners won't damage your tubing. To straighten tubing with different diameters, twist the adjustment knob to change the space between the wheels. Keep these straighteners steady by clamping them into your vise or mounting them to a work surface through holes on the base.