Aqualungs are amongst the oldest that I have serviced. I recently had to break the bad news to an owner of a very old Aqualung (1st stage looks like a flying saucer), that after contacting Aqualung’s technical support, I was told that that regulator could no longer be serviced & vital parts were no longer available. I have also serviced many old conshelfs & have had someone donate a very old Royal Aquamaster double hose regulator to the shop.