MARKAL PRO-LINE WP 96931 is a medium-duty, cold-applied, self-sealing weatherproofing and flashing compound. It is made of a superior blend of synthetic rubberized asphalt emulsified with extenders, reinforced with tough woven polyethylene fabric, and formulated with age-resistant additives for a long-lasting bond. It is designed for one-step professional weatherproofing of flashing and voids around windows, siding applications, pipe penetrations and masonry walls, and provides superior adhesion to most metals, masonry, concrete, wood, and many other substrates. It is self-sealing around fasteners, and also helps to reduce air infiltration and water seepage.