The flocked lined window rubber comes in two different forms and is suitable for sliding windows that need to retain a waterproof seal. No FWR148 is a preformed U shape and fits directly into a channel. The flat flocked strip, no FWR168, is ideal for fitting into different size channels. It is easily bent to form a U shape. Greater widths can be obtained by joining two pieces together. It makes an ideal replacement for Polyester ribbon.