increase strength of fingers ,wrist ,hand fitness and health suitable for children and old people Parameter materialpppackagecolor boxctn/quantity43*39 ... fingers, wrists, hands, forearms, biceps, triceps, ligament and shoulders.3,Great benefit for musicians, guitarists, pianists, drummers.4. ... , for example 8650 revolutions will display as 86.3. Real time revolutionsPress the FCN to select the ...