The zipper-backed weatherstripping from Prime-Line is constructed with dual fin protective barriers woven down the center of the white pile material at 1/4 in height. This waterproofing product highlights the insulating benefits of Owens Corning Air Sealing Technology�, designed to resist air, water, sound, mold, mildew, dust, and insects from entering the home. You can use it on virtually every window and door in residence to seal the gaps and leaks around the doors and windows, which allow outside air to enter, and inside conditioned air to escape. Replacement is easy with this 1/4 in. wide zig-zagged design. It features an easy-2-install installation method that permits you to quickly zip the backing into weatherstripping channels using any screen spline rolling tool. This Zipper Pile� is designed to simplify your door weather stripping projects with an effectively sealed perimeter around any home outlets. This pile weatherstrip comes in 18 ft. lengths with a Lifetime Warranty, and it�s guaranteed not to break down like other felt and foam tape weatherstrip products. This patented installation system allows you to easily zip insulation into existing window channels without the need to remove window parts or glass. Installation Tip: Simply cut through the length and center of the old pile backer with a utility knife and pull it out. And zip in the new pile with the installation tool.