#975 Sebs Elastomeric Flashing Mastic is a single component block copolymer elastomeric mastic that forms a tough and durable elastomeric membrane. Works great to patch and repair properly prepared existing EPDM, Hypalon, APP, SBS, BUR, PVC, fiberglass, wood and concrete. Exceptional elongation properties, cold weather pliability, excellent weather and water resistance, good chemical resistance, and is highly reflective. Makes an excellent sealant for horizontal and vertical seams and joints in a metal roofing system.