Once your gear is signed into the dive shop, the technician tests it for function before continuing with the service. The technician will check the instructions left by the owner to make sure there are no special notes. The equipment is then taken apart, and inspected for any broken "o" rings, or worn parts. The metal parts are degreased and cleaned in an ultra sonic cleaner, then the metal parts are rinsed off in hot water. The parts are dried and inspected for any wear and tear. The manufacturers overhaul parts kit for that regulator specifies which parts are marked for annual replacement. All other soft parts are inspected and replaced as necessary. The unit is then lubricated and assembled. The final tuning of the first stage and the second stages takes place. At this time, the last check of the equipment is performed. The intermediate pressure between the first and second stages is checked, the inhalation and exhalation resistance is checked with magnehelic gauge , and a vacuum test of the second stages is done. If everything performs according to manufacturers specifications a bill is written up and the regulator system can be returned to the customer.