Feature: 1. Built-in self-starting device, it can be started easily by pushing and releasing. 2. Long-term use of the wrist ball will effectively exercise the muscle groups of the arm and help fitness enthusiasts to perform targeted arm strength training. 3. Compact and portable, you can carry it around to exercise your arm anytime anywhere. 4. High performance rotor, very stable and little noise. 5. Made of high quality metal and ABS material, sturdy, durable and long service life. Specification: Condition: 100% Brand New Item Type: Wrist Ball Material: Metal + ABS Color: As Pictures Shown Size: Approx. 6.5 x 6.5 x 5.5cm / 2.6 x 2.6 x 2.2in. Package List: 1 x Wrist Ball Note: 1. The inside of the wrist ball is an overhead structure. Do not shake it or press the ball core hard, causing unnecessary damage to the wrist ball.2. Please do not shake the wrist ball irregularly or violently after starting the wrist ball, it will easily cause the sound of the wrist ball to become louder and difficult to start. Please rotate the wrist ball regularly by swinging the wrist or swinging left and right.3. Wrist ball is a high-precision product. Wrestling will cause the product to be damaged and unusable, and cannot be repaired.4. Do not add any oily or lubricating liquid to the wrist ball, it will make the wrist ball unusable. At the same time, when the wrist ball is running at high speed, do not try to stop it with the exposed part of the body to avoid bruising.