Teflon coated fiberglass tape with removable liner. Act as a protective barrier to hot wire contacts. Silicone adhesive. 3" core.Use 2" 3 Mil to cover the silicone sponge and channel. Put either 1/2" or 3/4" 10 Mil on the 2" for contact to the hot wire. The 10 Mil will remove easily when it needs to be changed.Other sizes available upon request.