This is a set of three MTX original mini basketballs and weight training balls, 160g and 350g. The weight training balls are for training the finger snap and release necessary for baseball. The MTX original mini basketball is a mini basketball for training the throwing and release feel of baseball. I purchased it from MTX Academy about six months ago. I think it will also lead to an increase in the number of rotations. 【MTX Original Mini Basketball】 An original ball that is perfect for training to cultivate the feel of the fingertips when throwing. It is widely used by children, amateur players, and top professional players. (From "Speed & Control in Power Position!") (※Air will be deflated for shipping) Size: ▼Diameter approx. 18cm This is a baseball training set that is also ideal for indoor training and can be used to improve ball speed and train body mechanics during winter training. There are scratches and dirt due to use, but it is in relatively good condition and can still be used. Please note that this is a used item, so please refrain from purchasing if you are sensitive to such things. Increase ball speed Fingertip strengthening High school baseball Amateur baseball Pitcher training Strength training