The Hand Trainer Powerball Wrist Trainer Ball Raining Apparatus Exercise Machine Training Arm Muscle Gym Fitness Equipment Relax|Power Wrists(Black) Features: Automatic start This product can start automatically, without the need for a traditional drawstring, push it to the end in the direction of the arrow and release the ball core to start. Practical The product also comes with variable-speed colored lights, and the speed can be adjusted to increase the fun of fitness. Decompression and relaxation This product can effectively alleviate the muscle and bone problems caused by long-term use of the wrist and arm, and can also help bodybuilders perform targeted strength training. Portable The size of this product is 7*5.5 cm/2.75 * 2.16 inch,compact and lightweight, easy to carry, and not occupying much space. Durable material Made of high quality ABS and Zinc alloy material, wear resistant and durable, owning long using life span. Specifications: Type: Wrist Trainer Ball Quantity: 1pc Color: Black Material: ABS+Zinc alloy Product size: 7*5.5 cm/2.75 * 2.16 inch(D*H) Weight: 270 g/ 9.52 oz Package: 1*Wrist Trainer Ball 1*wrist strap 1*ball bag 1*Package Box