Gents, This may sound daft, but I've never seen a decent description... When an air compressor is rated at so many cfm (cubic feet per minute), does that refer to air in its compressed state or at atmospheric pressure? I reckon there's about a 7 or 8 to 1 difference! Thanks, JohnP MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.