i don't know dive tanks but is this what your looking for ?
https://www.mikesdivestore.com/produ...0aAvS3EALw_wcB
The Beaver Cylinder Valve DIN insert fist most Cylinder Valves & Manifolds with G5/8” 232 Bar DIN EN-144-3 type outlets. It simply converts any 232 Bar DIN fitting for use with an INT-A-Clamp type Regulator 1st Stage.
Insert in to the DIN recess on a cylinder valve in seconds, tighten with a suitable 8mm Allen Key and easily removed to rapidly convert the cylinder valve back for use with DIN type threaded regulators.
video here https://www.youtube.com/watch?v=mybvNFzPeo8
i may not be on the right track mind you