Pro-Ties Bundling System - Green, 6/Pk. Invented by a hygienist. Made from 100% medical grade silicon that stretches up to 3 times its original size. Provides safer, faster way to sort and keep instrument set-ups together. Prolong instrument life by eliminating "tangled" piles of loose instruments and constant wear between mirrors and tips. Reduce the risk of stick injury. Will not stretch out of shape and rust .