Caulk putty effectively seals windows and more. Forms weatherproof seal on porous and non-pourous surfaces. Used widely as a gasketing material, sound deadener, insect barrier, and crack filler. Use with wood, plastic, metal, masonry, glass, and concrete. Fill 1/4" gap around windows or doors. Pliable, just peel and press into place with fingertip. Will not crack or harden.