This window track is ideal for window glass or for installing sliding cabinetdoors. Each channel groove is slightly (.005") narrower than 1/4"window glass so there is positive pressure against the glass at all times. It seals out leaks and preventsglass from rattling. Made of B-FLEX marine plastic, it will not crack or discolor. The elevatedslide at the bottom of the channel makes windows or doors easy to open and close. Sold in 8'lengths. White.