IB-3 StormStopper is a 50 mil mineral surface underlayment that is ideal for secondary water resistance under any roof in any climate. The self-adhering technology keeps the roof watertight even if the roof is damaged. Installs under roofing at edges, valleys, vents, skylights, chimneys to protect from leaks due to ice dams, melting snow and blowing rain. Comes with a selvedge edge for a secure seal on overlaps. Available in a 36" x 65' roll (195 sq ft). Packaged one roll per carton. 5-Year warranty.