... grade led Item No.: 868NC Product name:Wrist ball with LED and COUNTER Description:Shell material: A grade PCRoller material: Zinc ... musicians,guitarists, pianists,drummers.-Rehabilitates sore muscles and joints.COUNTER OPERATION-How to startPress the button ON/CLR to start ... The third symbol, while the rotor is stationary, this counter setting will automatically display the highest RPM ever achieved on ...