1/2 inch x 60 yds. 3M - 425 aluminum foil tape. Thermally conductive for heating or cooling efficiency and provides water proofing barrier and air leak protection. Premium grade. Aluminum backed tape features acrylic adhesive. Flame resistant, heat and light reflective. Improves visibility by magnifying light sources. Resists ultraviolet degradation ensuring long lasting performance. Meets UL 723, Class L File R 7311 and UL 764C.