Genuine Purdy replacement part. The Purdy Marathon paint roller is our most durable and productive knitted cover, made with a blend of nylon and polyester. Designed to hold more paint so you can paint farther per dip, this applicator is best for semi-smooth to semi-rough surfaces. Choose latex and oil-based paints and primers in flat, eggshell and satin sheens for the best results with this high-quality roller cover. Ideal for drywall, concrete, masonry and decks.