If you 're installing windows, or skylights and you 're not using capital STUFF Window & Door foam sealant, you 're probably asleep of a faster, cheaper air-sealing solution. It is a minimal-expanding foam with a blue pressure build that a serviceable, air-tight and water-repellent seal between a window or door frame and its angulate opening without bowing or bending the window frames. It 's the creative and door draft stopper.