Make Arm Great Again Strengthen fingers, wrists, hands, forearms, shoulders and bicep etc, and also be beneficial in promoting co-ordination and blood circulationThis certainly requires some fine motor skills in order to use The dominant hand/arm was easily able to keep the gyro ball going, that it will help refine your fine motor skills in that non-dominant hand armSmall, compact and transportable, you can take anywhere Simple to start with a pull-stringAnd the ball with flashing LED all you need do is to increase the speed by making a rotational wrist movement and to keep in sync with the spinning of the ballThe unit did not have any weird vibration to it Also having the silicone grip section is very nice as it helps with the gyro ball not coming loose from your hand You can attach it to wrist strap, if you are really concerned about the gyro ball flying away