Mortite is the original name in Do-It-Yourself caulking and it's still famous for its quality and versatility. Sure, Mortite Weatherstrip and Caulking Cord will seal windows effectively. But it's also widely used as a gasketing material, sound deadener insect barrier, crack filler and all around plugger-upper. It's available in classic grey or in woodtone to blend with brown or wood finishes.