Made with 100% medical grade silicone, completely non-carcinogenic and chemically inert. Electrical resistance measures infinity on ohmmeter, high dielectric strength. Comfort fit design adjusts to swelling due to pregnancy, diabetes, injury or arthritis. Able to withstand a maximum temperature of +300C (+572 F) and a minimum temperature of -55C (-67 F). Anti-aging properties allow ozone and UV resistance.