FST™ Duct Seal is a “closed cell foam” which is superior to “open cell” spray canned foams. The kit contains a two-barrel cartridge filled with a two-part foam base, which is mixed in equal parts as it is pushed through the mixing nozzle. When mixed and injected, the foam expands and hardens, keeping water, acids, greases, gases, insects, and rodents, etc., out of the conduit. The foam has good wetting and adhesion to metals, plastics, and concrete. A separate, reusable ratchet application tool is used to inject the foam.