FST™ Sealant is a two-part, high-expansion foam duct sealant. It keeps water, acids, dust, gases, insects, and rodents out of the duct. FST™ Sealant expands and hardens to a “closed cell”, rigid
structure. This permanent, but removable, seal blocks both water and gas under moderate pressure.


FST™ Sealant comes in a multi-use single plunger caulking tube package. The foam wets and adheres to metals, plastics, and concrete, and can seal ducts of different sizes, base materials, and shapes. It will conform around complex cable fill configurations. A kit contains everything required to install the duct
block (application tool available separately).