Throw Like a Pro Consistently & Effortlessly Made with 100% real Leather & Baseball Seams Provides Instantaneous Feedback Develops proper throwing mechanics for all types of pitches If the ball wobbles at all you're not throwing correctly. No Wobble = Proper Throwing Mechanics which will increase overall velocity & spin rate. Endorsed by Dr. Tom House, former major league pitcher for the Astros, Padres, and Rangers and owner of Bio-Kinetics, Marvin Freeman, former major league pitcher for the Atlanta Braves, and Lean Lawrence of the "AAA" San Diego Padres. A new design with a leather cover and seams has players raving about this product being new and improved. The Baseball Spinner will help pitchers, catchers, and coaches to better understand the rotation of the ball and what is required to impart that rotation. The Baseball Spinner is the exact diameter and weight of a baseball. It is a valuable tool to ingrain the proper mechanics of overhand throwing in all players. It can be used exclusively by pitchers for learning proper rotation on a baseball, which is required for movement, All pitches can be thrown with the spinner including fastball, split-finger fastball, curve, change, slider, sinker, and screwball. The Baseball Spinner is destined to make a positive contribution to baseball players and pitchers everywhere. The Baseball Spinner has been endorsed by Dr. Tom House, former major league pitcher for the Astros, Padres, and Rangers and owner of Bio-Kinetics, Marvin Freeman, former major league pitcher for the Atlanta Braves, and Lean Lawrence of the "AAA" San Diego Padres.