The Wooster 9" Pro/Doo-Z 3/16" Nap Roller Cover is a high-quality paint roller cover intended for professional painting use. The 3/16" nap indicates the thickness of the fabric on the roller cover. A nap of this thickness is appropriate for semi-smooth to semi-rough surfaces, offering adequate covering while maintaining a smooth finish. The Wooster brand is well-known for providing long-lasting and dependable painting tools, so you can expect this roller cover to function admirably and endure frequent usage. It's an excellent option for professional painters or anyone searching for a high-quality roller cover for their painting jobs.