•Ultra HT Wind & Water Seal® is a 45 mil, self-adhering roofing underlayment composed of a white, non-slip, cross-laminated polyethylene 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. •Ultra HT Wind & Water Seal® 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.