Can somebody clue me in to what this is? I have a request from a pair of divers for tanks with this sort of valve: DIN 25 x 2. I would like to be able to answer, but I am lost as to what this refers to. We have tanks with DIN valves, but I thought they were "universal," and in fact everybody who has come here to dive needing DIN valves has had no trouble with them. These divers are from Greece, if that helps at all.