The G7 BR2 Rangefinder is the only rangefinder that ranges and calculates your ballistic solution for any shooting condition. Here's how it works. The rangefinder is programmed for several ballistic parameters that are unique to your cartridge and firearm. Ballistic Coefficient, Muzzle Velocity, Sight Height and Zero Range are easily programmed on the device using the four input buttons. When selecting the MOA output mode no other inputs are required. If you are using a ballistic turret or reticle calibrated in yards, the BDC mode is selected and additional inputs for the Altitude and Temperature that the turret or reticle was built to match are entered.