The Bear Skin is a no-caulk, joint flashing for lap board siding that aids in preventing moisture from penetrating the butt joint. Bear Skin is a flexible 6 x 12 inch sheet of proprietary cross-linked, 7-layer, plastic film with a thickness of 6 mil (0.15 mm). After application, the tensile strength of the sheet gets stronger with time. On the back side is a 1.5 inch strip of adhesive for easy and repositionable application.