Our double-ended contour sanding blocks make it easy to sand both concave and convex shapes without distorting or diminishing the crispness of the profile. Each Sanding Grip has a convex profile on one end and a concave profile on the opposite end. The two ends are connected by a narrow flexible section that provides a comfortable grip, and can also be used for sanding. Made from a flexible rubber that adapts to minor variations in diameter. Grippy texture prevents abrasive slipping and hand fatigue. Set includes a total of six blocks with the following inside/outside diameters: 1/4'', 3/8'', 1/2'', 5/8'', 3/4'' and 7/8''. Diameters are molded into the rubber for easy selection.