CALDWELL BALLISTIC PREC CHRONO W/BLUETOOTH Whether you're testing load accuracy, monitoring the speed of your arrows, or ensuring your paintballs are within field regulation, the Caldwell Ballistic Precision Chronograph is the ideal tool for accurate velocity measurements.Capture shot velocity data via Bluetooth and record environmental conditions and load data in the Caldwell app. FACTORY CALIBRATED TO +/- 0.25% ACCURACY IDEAL FOR FIREARMS, ARCHERY, AIRGUNS AND PAINTBALL EXTRA WIDE SUN SCREENS FOR ADDED SHADING IN FULL SUN CONDITIONS CONNECTS TO YOUR SMART DEVICE VIA BLUETOOTH