Measure distance between pitcher and catcher with included measuring string and choose one of 8 predetermined distances (20′, 30′, 40′, 46′, 50′, 60.5′, 70′ and 80′)or for SPEED-KM (6m, 9m, 12m, 14m, 16m, 18.44m, 21m and 24m). GripSense technology begins to record the speed automatically the moment the ball is released. For pitching throwing training only, not to be hit with a bat or on hard surfaces. Measures speeds up to 120 MPH.