A cement-based, quick-set hydraulic cement for concrete and masonry. It is a dry powder mixed with water to putty consistency that sets in 3 to 5 minutes to stop flowing water or seepage under pressure through holes and cracks, and can even be applied under water. It expands as it sets to provide a permanent, high-strength patch. Ideal to repair holes and cracks in concrete and masonry walls, wall-floor joists, swimming pools, water storage tanks, fountains, ponds, and drains. Also for sealing around pipe/conduit or to anchor hooks, metal to concrete. Coverage: 1 pound fills a crack 3/4" W x 3/4" D x 2.5' L, or 16.8 cu in.Warning:This product contains crystalline silica a chemical known by the State of California Proposition 65 to cause cancer.Risk of cancer is based upon breathing of silicia dust particles with prolonged occupational usage over many years.