Bintiva Heavy Duty Replacement Door Anchor for Resistance Band Set Heavy duty construction - the door anchor is designed to withstand any, and all uses. Dense foam provides ultimate safety for the user, and will not damage, dent, or scratch, the door. The door anchor's large diameter ensures that it can be used at any point of the door, even if these is a large gap at the top or bottom of the door. Thick webbing, high quality stitching, and a heavy duty core ensures ultimate user safety. Like all Bintiva products, the door anchor is backed by a 100% manufacturer's warranty.