Here at Algar Air we measure the amount of air provided by your Air Compressor in CFM which stands for Cubic Feet per Minute. This is most important information when buying a new compressor or wishing to add to the system for 2 reasons. Firstly, and most obviously, you need to know the total consumption of the equipment that will be using cfm so you can size you compressor correctly. Secondly, if you are buying a Piston Compressor, manufacturers supply two sets of data for CFM; a displacement figure which is what is produced at the pump but the one you need is the FAD (free air delivered) which what you actually get at the outlet. It is important to make sure that when buying a piston compressor that you get this FAD figure as that is what you need to match to your consumption.