Purdy 140670122 White Dove High Density Woven Covers 3/8" Nap Cover. Purdy's most popular roller covers . use with all paints and exterior stains, especially where a smooth, lint free finish is desired. White Dove series features a high density woven cover, made of Dralon, a derivative of nylon, which enables the paint to flow freely into and out of the cover for easy rolling and a high quality finish. White Dove covers feature thousands of miniature flagged filaments so paint leaves from thousands of tiny surfaces for a smooth, virtually perfect finish. The high density acrylic fiber is also capable of carrying large quantity of paint, leading to improved efficiency and productivity.