11.5" in length. Use wrench to securely fasten band-it style free end clamps, roll band and clips or band-it Jr. style preformed CV boot clamps. The mandrel tightens the clamp, holding it in place until the ears of the clamp are folded down This wrench is used to securely fasten band-it style free end clamps, roll band clips or pre-formed CV boot clamp. The tool is used by turning the winding mandrel with a wrench. The mandrel tightens the clamp, holding it in place until the ears of the clamp are folded down..