wrist exercise ball, hand grip strengtheners , hand power grip ,hand grip Tone your arms &strengthen your hands hand grip Model:JRT-812010171.Material:PP+ ... 4.Self-contained mechani wrist exercise ball, hand grip strengtheners , hand power grip ,hand grip Tone your arms &strengthen your hands Model ... the foam3.Spring Dia:4.0/4.5mm4.Foam handle:common & environmental matrial5.Inspection of Import and ...