Features: brand new and high quality Chinas traditional hand sports equipment has a history of thousands of years. The method of use is very simple: put 2 or more iron balls in your hand and let it spin. The surface is enamel, hollow in the middle, can ring the bell. Keep your hands, fingers, wrist, and arm healthy. Recommended by hand therapists, using baoding balls can strengthen your hands and keep them flexible helping to manage hand conditions such as arthritis and nerve damage. Many other benefits such as keeping your hands busy to stop bad habits, improve circulation, help with for chi and meditation, increased concentration, and more. 100% Satisfaction Guarantee, please contact me if you have any questions.Thank You Package Includes: 1 Set Baoding Balls Specifications: Color:as picture shown Material:enamel Sales Way:Retail, Wholesal,Drop Shipping Size: One Size Length:4.7cm(1.85in) Width:4.7cm(1.85in) Height:4.7cm(1.85in) Quantity: 1 pair note: If you have big quantity (only need over 50 dollars), please feel free to contact me, I will give you SURPRISED PRICE(The more the quantity, the lower the price), thanks Size For Manual Measurement, there may be a 0 to 2 for cm error, belongs to the normal phenomenon. And due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you