FROTH-PAK Foam Sealant seals difficult areas to help unwelcome air leaks and help lower heating and cooling costs by properly insulating and air sealing. This quick-curing, chemically cured polyurethane two-part foam is intended for professional use only with appropriate safety equipment. It seals gaps and penetrations less than 4" wide, including vents, ducts, pipes, cables, junctures and rim joists. Highly portable it doesn't require an external power source, has a one-hour re-entry time and is tack-free in 30 to 40 seconds. It requires component B, gun assembly (not included).