... Zinc-alloy and a grade ABS LED: 6pcs a grade led Item No.: 868NC Product name:Wrist ball with LED and COUNTER Description: ... Shell material: A grade PCRoller material: Zinc-alloy and a grade ABSLED: 6pcs ... strength in fingers, wrists,hands,forearms,biceps,triceps,ligament and shoulders.-Great benefit for musicians,guitarists, pianists,drummers.- ...