<p>#1 Seller for Boiler Feed Water and Bad Blows | Heat curing, Black color, Extremely dense, Fibrous putty impregnated with metal and ceramic fibers. Shelf-life 6 months in closed packages. Must store in refrigerator or freezer. </p><h2>Applications</h2><p>Clamps, Enclosures, Perimeter Seals, Wire Wraps, Flanges, Boiler Feed Water, Steam, Condensate. Designed for bad blows. Can be used for killing or plugging valves or lines no longer in use. </p>