Willseal 150 is a precompressed, self-expanding polyurethane foam joint sealant that is designed to seal against rain, wind, sound, draft, and dust. Unlike other conventional methods, Willseal 150 is not susceptible to breakdowns caused by excessive joint movements, joint strain, surface contamination, aging, and general tensile stress-caused failures. It does not dry out, shrink, or deteriorate. There’s no mixing, no masking, no staining, and no mess. Willseal 150 can be installed under many weather and temperature conditions.