Look Bob the real reason for DIN not being in favour with the Yanks is pretty simple
Its to retain American domination of the recreational market regulator share pure and simple.
It was a consideration that I was not going to bring this up on an open recreational forum. None the less I did think that a pure engineering solution would have been acceptable for a retail open forum.
Never the less DIN is by far a better solution but there is one glaring reason that DIN wins and I have not offered this for consideration so far
The simple answer is that DIN is cheaper to produce in smaller batches and cheaper to manufacture in even small batch quantities.
Now if you consider US Divers were back then making A clamps from hot brass stampings in quantities of 10,000 at a time just in order for the tooling to be amortised.
Now by contrast consider a small engineering design house in Europe having to invest in the tooling and investing for 10,000 blanks from the get go pretty much kills off your investment cost before you even start to consider the stamping cost for the second stage box top filter solder jigs and fixtures.
By contrast DIN is the solution. Two simple parts easy to machine from standard brass bar stock and in an economic minimum run of 60 components brings younger leaner fitter smaller and smarter players into the sports diver regulator game.
The old yankee guard of USD Scubapro et al are all up in arms over this as they cannot have these small upstarts companies competing with the major American brands so they insist on the hard to make in small quantities A clamp yoke design as the de facto design standard
Then they get PADI and the like with fanboys chirping away that the A clamp is better and guess what here we are in 2022 with this left over remnant of the old guard on their collective knees as clarity dawns and DIN makes its move on the lack lustre
American brands who by this time are dependant on imported crap from China with their little badge on and imported neoprene from the Far East and paying huge pay checks to old men who used to swim in the Olympics for allowing their name on a pair of cheap swimming goggles and paying out for guru status Brand Ambassadors for sh*t for grins stunt dives.
While the young fit and lean are using the money saved from not using the expensive old A clamp stamping and are using the money saved into plastic extrusion moulds that only requires the add in of a basic engineering mechanical design and you now have a regulator on the market that can be cloaked into any polymer shaped potential market leader in DIN. Payback is a bitch.