For massive leaks and flooding, Flex Paste maximum penetrates deep into large cracks and holes to stop leaks fast. Save more with our largest size ever, and get more coverage for your indoor and outdoor projects. Flex Paste is a super thick rubberized paste you can use to spread, shape, form and seal virtually everything. Flex Paste starts out as a thick paste and dries to a strong, flexible, rubber coating. It can be applied to all types of surfaces to seal out air, water and moisture. It clings to the surface and instantly fills large gaps, cracks and holes. It won't shrink or wash away and can be painted any color. Flex Paste can be applied on dry or wet surfaces, even underwater. Flex Paste clings to a wide variety of surfaces and will work on wood, glass, tile, concrete, aluminum, metal, brick, stucco, masonry, copper, fabric, fiberglass, ceramic, porcelain, natural stones, roofing, PVC, EIFS, EPDM, CSPE, Hypalon polyurethanes and so much more. Color: Black.