Second Skin Multipurpose Butyl Rope - Waterproof Adhesive Sealant for Cars - 3/8" X 15' - Made in the USA Damplifier&trade; Butyl Rope is a premium grade sound deadening sealant that maintains permanently flexibility. Excellent for auto glass installation to provide a flexible and waterproof seal. Seal and cushion speakers in a box or inside of a vehicle. Perfect for use anywhere that a watertight seal is needed. Premium quality butyl rubber with a thermal range of -40 degrees F to 250 F. Proudly Made in the USA.