WRS 7/8" x 1/2" Glazing Channel Weather Stripping - 50 Ft RollThis is a fin seal pile weatherstripping. The fin seal runs down the center of the pile, this thin plastic strip help to reduce air, wind, and water infiltration. This weatherstripping provides superior weatherability and chemical resistance and is designed to be low friction. This weatherstripping is sold in 50ft lengths. Backing width: 1 2" Pile Height: 7 8" Used in aluminum or vinyl windows at the top and bottom of single or double hung designs.