AIRs or alternate inflator regulators are essentially octopus second stages built into the inflator mechanism of your BCD. In an out of air emergency you swap to this and pass your out of air buddy your primary second stage. Traditionalists are always keen to stick to the most common configuration of primary second stage and octopus. However with more people travelling to dive, weight and bulk of kit has started to make the AIR solution a more obvious option. AIRs save you the weight and bulk of an octopus second stage and it’s hose. You already require a BCD inflator and when upgraded to the AIR it does not add much weight. No need for an additional hose as the one feeding your BCD inflators supplies the regulator within the AIR.
The AIR fits to your BCD inflation hose.
Years ago AIRs where temperamental beasts suffering poor breathing performance and often were never quite the same after having been serviced, never seeming to settle down again. However these problems have long been overcome and modern day AIR systems are easily fitted to your BCD and are often less expensive than an octopus. Urban myths like you could not inflate and breathe from the AIR have been relegated to history. With all this in mind why are they not more popular? Is it lack of understanding of the system? Lack of training? It’s only briefly mentioned in diver training. Is it self survival? Why give away your expensive high performance primary regulator and go onto the £115 back up? It should be noted that generally you should only fit an AIR to your BCD if it is the same make and the manufacturer (or your dive centre) confirms it is compatible (there are a few exceptions).
The pros and cons:
Currently available are the: Mares Air Control, AP Valves APV100 , Atomic Safety Second 1 and Scubapro AIR 2 systems.