Caldwell’s Ballistic Precision Chronograph provides accurate velocity measurements across a wide range of shooting conditions. Higher accuracy was achieved by using a high speed 48 MHz processor and by designing a circuit with an advanced data interface that allows each unit to be computer calibrated at the factory after assembly. The end result is the ability to provide much better accuracy than other chronographs on the market (+/- .25%). Although technologically advanced, the unit is designed to be simple to operate, displaying velocity in Feet per second or Meters per second on the large built in LCD screen. The chronograph can also deliver the shot string velocity data through the 15 foot audio jack cable (included) to smartphone/ mobile device.A free App is available for download that displays the velocity of each shot on the phone screen and records it with other data identifying the load and environmental conditions. The App also automatically calculates Average Velocity, Standard Deviation, Min, Max and Velocity Spread for the shot string. The data is stored and can be exported via Email or simply recalled for reference at a later date. The sunshades are extra wide for better reliability on sunny days and are constructed of a durable synthetic material. Measures from 5 to 9,999 FPS. There is a -20 threaded insert on bottom of housing for tripod mounting, operates on a 9 Volt battery (not included).