RAD Rounds have the small size and pinpoint precision to mobilize muscles that other tools can’t touch. With three sizes and three different densities, these balls serve up infinite options when it comes to tackling your tough spots. Purchase includes one large, one medium and one small RAD Round. Use with the RAD BLOCK for additional leverage and stability. Dimensions: Large round 2.2" diameter, medium round 1.6" diameter, small round .75" diameter. Materials: Silicone. Color: Large round green, medium round blue, small round black. Unit weight: Large round 3.6 oz, medium round 1.6 oz, small round .3 oz. Comes with PDF guide of exercises. Green= Soft, Blue= Original, Black= Stiff.