Ultra HT Wind Water Seal is a 45 mil, selfadhering roofing underlayment composed of a white, nonslip, crosslaminated polymer film, laminated to a high temperature rubberized aggressive asphalt adhesive Product is engineered for whole roof protection under shingle, tile, shake and metal roofing systems It bonds to the substrate and seals around fasteners to limit damage caused by water penetration or leaks It is ideal for secondary water resistance with proper roof ventilation Product comes with a split release liner for easy installation in valleys, ridges and around chimneys