So my question is.. i've decided I want the Suunto Cobra, but I am not sure which model. I can find info on the Cobra and the Cobra 3 on Suunto's site, but can't find any information on the 2? Can someone shed some light on the differences? Or what's in the 2? and what's the difference between the Cobra and the ones labeled "Air/Nitrox" They all do Nitrox right?