Devcon Epoxy Adhesive Dfense Blok is a two-part epoxy putty stick ideal for sealing cracks and holes in metal, wood, concrete and more. It cures in 2-3 hours with an extremely hard, durable finish that stops leaks, resists chemicals and withstands temperatures up to 300°F. This gray putty can be sanded, drilled, tapped and painted when fully cured. It has a 1 year shelf life when stored properly. The twin tube package contains 1 pound of material, allowing repairs of holes up to 4" in diameter.