BEST ALL-ROUND & EXTENSOR EXERCISER - 1) Works as a hand ball (light and medium tensions) for increasing strength and range of movement. 2) Exercises the frequently ignored extensor muscles to guard against and help relieve the symptoms of carpal tunnel, arthritis and repetitive strain injury. 3) Provides basic grip training for rehabbing hands. RESTORE STRENGTH and dexterity; this device is great for OT following injury, stroke or postoperative after surgery; reverse and your hands against arthritis, carpal tunnel, tendonitis and occupational RSI; works for both left and right hands GREAT EXTENSOR EXERCISE FOR ATHLETES and MUSICIANS - completes a performance focused workout for any serious athlete or musician, by exercising the weakest hand muscles - the extensors. Alongside targeted grip training, hand flex training can help overall speed, strength and fluidity of many sports and performances - get the edge and make the decision to add this into your practice routine now STRESS RELIEF for adults; sooth and cool your stress by squeezing for as long as you can; focus on the tension building in your muscles until they to fatigue and then feel the relief as you release and let it all go colour: Material:TPE size:Diameter: 105mm Package Contents: 1 * Grip ball Only the above package content, other products are not included. Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.