Wincspace Wrist Trainer Power Arm Strengthener Essential Gyroscopic Wrist And Forearm Exerciser Ball (Blue)gyro ballForce ballpower ballmagic balls get model sport nowIf you dont know how to play it,can search video via youtubeIt is fun and good for hands,wrist,shoulder, forearms,biceps and good as warm-up sport before you do climbing,golf,basketba..