timesport upgraded auto-start power wrist ball spinner gyro hand grip strengthener wrist forearm exerciser with led lights (black) timesport use our auto-start wrist ball, as the speed of the gyro increases, the centrifugal force also increases, and the reaction force on the wrist increases,we can enjoy muscle training freely in anytime, anywhere.<p> <b>how to start your new wrist ball. </b><p> actually, starting this gyro ball is very simple. you only need to make some practice and then you can master this skills. now, we recommend you proceed as follows: <p> step1: take the gyro ball in your hands with the rotating core facing up and then use both of you thumbs to turn the rotator again and again ,up to the corresponding elastic core position along with the arrow direction. <p> step2: hold the wrist ball tightly and then release yours thumbs off the rotator immediately, the rotator will be running at the speed of 1500 to 3000 rpm. at the same time ,turn your palm down slowly rotating your wrist to get the power to maintain the existing gyro ball or higher than the starting speed.<p> step3: when you turn the core speed up gradually , you will feel the same synchronous growing reacting power on your wrist and your arm with the rotating gyroscope. when you reduce the circle diameter your wrist draw , the speed will be up. the smaller the circle diameter, the faster the rotation of the core will be meanwhile ,the more difficult the wrist will feel to move.<p> <b>package contents:</b><br> 1 * power wrist ball<br> 3 * extra non-slip silicone ring<br> 1 * safety rope<br> 1 * user's manual in english