For use on any machine weight stack. Allows you to increase resistance in 5 increments. No need to jump in 10, 15 or 20 lb. increments any longer. Features thick, protective virgin rubber molded over a solid steel core for a lifetime of trouble-free use. Will not slip, slide or fall off Will not damage weight stack or machine Overall Dimensions: 4" (L) x 5" (W) x 1.5"(H)Item Weight: 2.5 lbs.