These cable ties are made from a durable nylon (polyamide 6.6). Quickly and safely; Emits a slight angle to the tip end a easy insertion into the head of the sunglasses. Inner teeth on the cable give easy, secure hold by hand or through appropriate tool. Polyamide 6.6 is halogen free, silicone-free, highly flame-resistant (except self-extinguishing) and tough.