The Accardis Beer System device screws onto the headcoupler of the keg. There are no lines to cut into. Simply uncouple the keg, screw the device on and screw the beer line onto the device. This device will measure how many ounces left the keg in one ounce increments. There is a readout on the face of the device. Just take a reading each day or each shift, record the number, and determine how much beer was used for the period. The counter can be reset to zero at any time to start over or when you tap a new keg. An Excel spreadsheet comes with the device to calculate what was used, how much is left, how many glasses were poured, etc. This device is simple to install and easy to use. Start controlling your draft beer now!