ZETT Training Ball Tee Training Ball for Practice Batting and Toss Batting With iron sand inside, the ball with a weight (about 450 g)), it is difficult to fly forward if you cant properly catch the core, so you can understand the meat points. You can also train your wrist at the same time, and you can also train your grip strength for other than striking exercises. ■ Body Material: PVC; Inner Material: Iron sand; Weight: 15.7 oz (450 g); Country of Origin: Taiwan