The Mayhew Tools Heat Stabilized Cable Ties are designed to withstand temperatures of up to 250 degrees F, accommodating fastening automotive cables and wires in high heat conditions without the worry of melting or warping. The line of heat stabilized cable ties are UV resistant, safe for indoor and outdoor use, and are a combination of nylon 66 (which provides high mechanical strength and stability under heat and/or chemical resistance) and a heat stabilizing additive. They are made in the U.S.A.