Bestt Liebco® Roller Cover, series: Master, 3/8 in Nap, 4 in Length, High Density Foam. Bestt Liebco® Master roller covers are the perfect blend of performance and value. Designed for the professional painter, these versatile applicators are engineered to deliver an outstanding finish in less time with less effort. Sherwin-Williams® 559424600 Bestt Liebco® Master Roller Cover, 3/8 in Nap, 4 in L, High Density Foam, Professional Grade