Markwort Speed Sensor - Baseball Press start, throw the ball, and the LCD indicator displays pitch speed in MPH upon impact. Official size and weight of a regulation ball, but used as a training aid for any age or skill level. Measure distance between pitcher and catcher with included measuring string. Speed Sensor GripSense technology begins to record the speed automatically the moment the ball is released. For pitching and throwing only, not to be hit with a bat or on hard surfaces. Instructions included.