The Barrow Silicone bending cord is designed to assist you in more efficiently and accurately bending or shaping your hard tubing.In order to bend rigid tubing without breaking it, you must use a heat gun to soften the tubing and make it flexible. While it is in its flexible state the walls are capable of collapsing in on themselves and ruining your tubing. Using a silicone insert will prevent the walls of the tubing from warping or collapsing during the heating and bending process.Each bending insert measures 1M in length for use with most rigid tubing of it's size. Barrow Silicone Bending Cords available in 12mm,10mm and 8mm sizes and can only be used with their respective tubing.