Description: Premium QualityThe hand exercise gripping rings are made from premium silicone, suitable for Gripper, stretch, and pull. The nonslip rings are also torn and crack resistant for long term use. Perfect SizeOuter diameter 7.7cm/3.03inch,Inner diameter 3.8cm/1.50inch, Thickness 2.1cm/0.83inch, Perfectly sized for grip strength training for men, women, seniors, and teens. The muscle training rings offer resistance and fill your hand. Grip StrengthenerStrengthen wrists, improve the dexterity of your fingers and increase the strength your hands can apply while reducing fatigue. The hand gripper helps balance your grip muscles and your expanding muscles. Easy to CarrySuitable for all age groups and fits well for all hand sizes. Portable compact design, hand gripper is convenient for training fingers, hands and forearms throughout the day at home, office, watching tv, rest, etc. Widely UsedIdeal for athletes(tennis, basketball, boxing, golf, and rock climbing)and musician (guitar players, bass players, pianists, and violinists), computer workers. great gift choice for families, friends, colleagues, etc. Size Chart: Outer diameter 7.7cm/3.03inch Inner diameter 3.8cm/1.50inch Thickness 2.1cm/0.83inch Package Includes: 1 Hand Grip Exerciser Note: Please allow slightly errors due to manual measurement and different monitors.