This is Minorman's Amazing baseball training aid, the Trunk Ball. By wearing the strap around your neck and holding the ball between your wrists while batting, you can expect to improve your palm-up technique. Also, by holding it between your thighs during batting practice, you can aim to strengthen your adductor muscles. I bought it intending to use it for practice, but I ended up not having the opportunity, so I'm selling it. It's a product that has only been inflated once and is undamaged. If you've been wanting to try it, how about it? Shipping is included. Please check the first image for the condition. Includes an air pump and strap. The air will be deflated for shipping. Thank you.