This is the XS Scuba DIN Fill Adapter For Scuba Diving Regulator Features: Adapt DIN valves for filling with a standard yoke filler Fits all 200 and 300 bar DIN valves Rotating DIN handwheel Standard inlet and outlet O-rings (p/n VP15-V) Viton O-rings ABOVE WATER USE ONLY. 3442 PSI MAXIMUM. This adapter is designed to allow the filling of cylinders with 200 and 300 bar DIN valves from standard yoke fillers. "