Closed cell Handi-Seal was especially formulated for installation of new windows and doors. Its minimal expansion properties eliminate the “bowing” problem associated with many foams. This property makes it an excellent product to use on any project where the foam will not be visible (it is a gray color and has a styrofoam-like appearance). It is very easy to use. Just attach the straw to the nozzle of the can. This long straw makes Handi-Seal an excellent product for touch-ups and for reaching into small openings. The output of closed cell foam provides a superior thermal insulating barrier compared with fiberglass and caulk.