Just a heads up: Zeagle switched to an Air2 knockoff, and so the current Zeagle (Octo-Z) falls in category 3 now. Just letting you know since you are the man with the info for so many people.
Mares Air Source also falls into that category, though there version of the hose looks different.
And technically there is a difference between the Apeks/Old Zeagle and the USD/Oceanic hose. Though they are usually interchangeable, there is a difference large enough to make things sometimes not interchangeable. It's really only noticeable with the aftermarket fitting to turn standard LP hose into the specialized hoses, or in the thing to make a tire inflator work with one.
As I have found out, I gave some bad info here. I was looking at bunch of these together.
The Mares is called the Air Control, and it uses the same hose as the old Beauchat/Apeks/Old Zeagle, not the Air2 style hose.
As noted above there are three distinct hose styles:
1. Air2, and copies of it including the new Zeagle Octo-Z
2. USD/Oceanic
3. Old Zeagle/Beuchat/Mares
As a thread about miflex hoses not fitting some Aqualung alternate inflator regs pointed out, 2 and 3 can sometimes use the same hose (and both do just fine with the factory supplied fitting on each other), but some aftermarket adaptors fail to work. What makes it harder to deal with is that Zeagle use to make the Aqualung version (branded as a SeaQuest product), before Aqualung started making it for themselves, so an Aqualung dealer will have two hoses that are almost but not quite identical. And may not even know the difference, because they usually (but not always) work with each other.
I know until I started playing with some after market stuff like DiveAlerts, where some worked and some didn't on both the hose end, and the Alternate inflator nipple, I had no idea that 2 and 3 were actually different, because most of the time (but not all the time) they are interchangeable.
http://www.scubaboard.com/forums/bu...9817-seaquest-scubapro-alt-air-fitting-2.html
That thread is an example of the confusion. Because 2 and 3 are near matches, and switching hoses works for most people, it is really confusing when, due to manufacturing tolerances, some random person's stuff does not work. What is even more confusing is that the aftermarket sometimes is aware of this and sometimes not. I have seen a Beachat specific DiveAlert, but they no longer maintain the distinction, and sell one that fits all 2 and 3 that is a match for the Oceanic one.