Designed to test the high power airsoft shooting speed, muzzle velocity, shooting kinetic energy, and the predicting shooting distance HD LCD screen with backlight, easy to check the readings accurately even at night, testing error less than 1.3% IR sensor self-calibration technology, customed weight and caliber value, data playback, auto power-off Compact size has a 25mm extra-large size diameter aluminum caliber which even allows you to test the velocity of the paintball Comes with a detailed user manual, easy to use with only three buttons. NOT includes batteries!