ButySeal is self-adhesive butyl sealing tape, with one side lined with aluminum foil. 

ButySeal is self-adhesive butyl sealing tape made of high quality butyl (butylene). It is suitable for sealing in case of water ingress on roofs, including sheet metal, building cracks, asphalt sheets, panel joints, tile roofs, chimneys. It is protected by a metallic aluminum film, making it extremely resistant to aging and oxidation caused by atmospheric and chemical agents.