The patent does not contain asbestos fireproof coating, surface attached to the checkered aluminum foil surface. With simple or multiple one inch or more flexible conduits and cables of non-flammable, return air duct fire protection. Suitable for PVC, CPVC, PP, ABS and other materials. Heat resistance, and it can be easy to install in new construction or installed directly on the existing fire-fighting equipment. UL1709 test.