Tradon Strong stainless steel extension springs and solid steel hinges both build a perfect hand grip strengthener for your daily training for long time Rubber Ergonomic Handle and Non-slip Gripper: The Ergonomic handle and its non-slip gripper fits well for all hand sizes, perfect for men and women, seniors and teens Adjustable Accurate Resistance: The adjustable dials could be adjusted from 20-88Lbs (10-40KG) just by screwing in or screwing out the knob just like the right picture shows It's a perfect training gripper if you suffer from rheumatoid arthritis, carpal tunnel, tendonitis, tennis elbow or just right on the way to recovery from a fractured or broken wrist, or tendon surgery Practical Necessary: made for improving strength, power and speed in the wrists, fingers, forearms, hands, and helps to relieve stress. for athletes, musicians, pianists, rock climbers, golfers, bodybuilders, tennis players and more.