The LOX Fill, Buildup and Vent Valve is a semi-automatic valve that provides a safe means to control flow during filling operation of liquid oxygen converters. A specially-designed valve connection mates with standard LOX ground handling devices. When coupled to this device, the internal valve mechanisms simultaneously allow for the venting of oxygen gas within the converter and the transfer of liquid oxygen into the converter. When disconnected, these mechanisms automatically close, allowing the pressure build-up process to begin. The Essex LOX Fill, Buildup and Vent Valve is a CRU-50/A connection and is QPL approved to MIL-V-25961.