This CRL Finned Weatherstrip maximizes the energy efficient qualities of fiber pile by adding a patented, solid barrier fin. The center fin stops air, water, dust, and insects from infiltrating cracks around windows and doors that use pile weatherstripping. The polypropylene fiber pile resists mold, mildew, and corrosion, and has exceptional resistance to abrasion. It is silicone treated to repel water, and stabilized against ultraviolet and ozone. The backing strip is polypropylene and lasts longer than plastic weatherseals. CRL Finned Weatherstrip will replace approximately 90% of the existing storm window pile weatherstrips made, and is installed by simply snapping it into the pile channel of the existing frame.