The Caldwell Ballistic Precision Chronograph is a must have for a variety of shooters from handloaders trying to optimize load data to archers and air gun enthusiasts. This chronograph will provide an accurate velocity reading from speeds of 5 to 9 999 fps within ( /-.25%) accuracy. Caldwell achieved this level of accuracy by using a high speed 48 MHz processor and calibrating every unit after assembly before it leaves the factory.