I'm not a DIR diver - my opinions on AIR2 systems were formed when I owned such a system as a novice diver. I went to a scuba convention in the UK and made a spontaneous decision to buy a A.P.Valves AIR2 for my Buddy Commando BCD....because it seemed like a 'great idea'.
Within 20 dives, the AIR2 was sold second-hand. I hated it. I lost money on it, because this was well before the advent of Ebay..
Here's my opinions about the claims made for AIR2 systems (
i.e. why I was tempted to buy one..and why I regretted that decision);
Convenience: One less hose. Yes... there is one less hose. But... what you end up with is far more bulky and annoying than a lightweight AAS on a dedicated hose. AIR 2 systems dangle terribly. They are more awkward to use for buoyancy control. Also more awkward to use for air-sharing. Compromising on two essential functions, leads to the diminished performance of
both functions. You have to donate the primary with AIR2... which means that you need a
longer primary hose. Two steps forwards, one step back. What overall convenience are you actually achieving?
Hoses: You need a specific LPI hose for use with the AIR2. This means that you can't rent, borrow or otherwise use any other regulators. If I had a dollar for every request for loan of an AIR2 compatible LPI, or to swap hoses on our rental regs etc..... Also... good luck in getting a replacement hose at short notice in most tropical/tourist destinations or on a dive boat, should your regs fail...
Streamlining: One less hose again.. BUT... a big bulky AIR2 is nowhere near as streamlined as rigging a bungee necklace AAS, on a 22" miflex hose. Nor as comfortable. Nor as easy to use. Again... the issue of requiring a
longer primary hose to facilitate primary donation.
Weight: AIR2, plus hose, will weigh more than a lightweight AAS on a short braided hose. It all adds up, if you are travelling regularly and get hit with airline excess baggage charges.
Donation: AIR2 gives you little flexibility for air-sharing. You
have to donate the primary, which few divers are trained to do. You
have to have a longer primary hose to allow that (
wasn't the idea to reduce the inconvnience of hoses?!?). You
have to manage your buoyancy on ascent, through an LPI that is now stuck in your mouth (
hardly convenient or the least task loaded method).
The bottom line:
If you want a convenient, lightweight and easy-to-use system.... get a lightweight secondary regulator (i.e. Mares MV) and stick that onto a 22" miflex hose... and then necklace bungee it around your neck. You still have to primary donate, but you have reduced weight, reduced bulk, achieved more hose streamlining and not had to compromise on your emergency OOA drills or complicated air-sharing ascents.
There's nothing 'wrong' with AIRII systems, but I don't think they are optimal. I also think they promise much more than they actually deliver. I would never say 'don't get one'.... just advise to
try before you buy and have an open mind and, also, don't be naive about some of the claimed benefits. Consider the alternatives and, where possible, try them all.
Nice concept - but not matched by the reality.