Graphic Blue-Runner dampener cover is made of specially formulated fibers to insure maximum performance and durability. This list free, pattern free material lasts 4 to 10 times longer than cotton. It's multidirectional manufacturing makes adjustment to the roller a breeze. Specially treated fibers for optimal water absorbancy. Various sizes fit rollers from 3/4" (19mm) to 6" (152mm) in diameter.