Colorful Metal Self-Starting Wrist Ball Fun Decompression/Gravity Challenge/Strength Mastery Quality Assurance Self-Starting Device Fine Inner Core New Lanterns No Charging Required Simple Operation Are You Still Upset? Long-Term Use Of Mouse Cause Wrist Pain And Weakness Long-Term Training Transition Cause Wrist Pain A Wrist Ball Easily Solve Problems Feel The Strength Of The Rotating Shaft With The Rotation Of The Wrist It Can Not Only Exercise Wrist Strength But Also Release Pressure Mechanical Structure The Ball Core ls Made Of High-Quality Carbon Constructional Steel With Stronger Hardness And Greater Degree Of Shock Buffer, High Stability, No Cracking, And More Resistant To Manufacturing No Power delivery Required Interaction Between Wrist Rotation And Internal Ball Core Centrifugal Force ls Generated To Maintain High-Speed Rotation Of The Core Self-Starting Clockwork It Can Be Smoother When Pushing Forward More Fun And Exciting Strong And Shatter Resistant High Strength Elastic Coefficient Impact Resistance Aging Resistance Variable Speed Colored Lights With The Acceleration Of The Rotation Speed Of The Ball Core, The Light Will change Color, increase The Sense Of Rhythm And Decrease The Pressure Wrist Rope Protection When Using, Put On A Dedicated Wrist Rope To Avoid The Ball Being Thrown Out Due To Too Much Strength During Playing, Which ls Safer To Use Self-Starting Device Built-In Self-Help Elastic Device Can Be Started With One Push And One Put Easy Three-Step Play Step 1 Press The Ball Core Gently With The Thumbs Of Both Hands Push In The Direction Of The Arrow Until The Ball Core Becomes Unable To Roll Due To Greater Resistance Step 2 Quickly Release The Thumbs Of Both Hands That Are Pressing The Core Of The Ball, And Hand The Ball To The Ball Holder To Rotate Step 3 "Feel The Power Of The Ball Turning Use Your Wrist To Move The Ball In Circles, And Follow The Strength Of Your Hand To Continue To Accelerate" Controllable Power Pure Mechanical Design, With The Rotation Speed increasing, The Centrifugal Force Becomes Larger, The Unique Sound Waves And Colorful Rhythm increase The Fun By Strength Mastery Product Display Product Information Product Name:Self-Starting Wrist Ball Specifications:70*70*55mm Core Material:High Quality Carbon Constructional Steel Shell Material:Polycarbonate Silicone (Anti-Slip Ring) Note: The Product is Measured Manually, And Some Errors Are Normal