Micro Matic Primary CO2 Regulator (60 & 3000 PSI) 
A primary CO2 regulator by Micro Matic.
The gauges go to 60 and 3000 PSI, and the regulator has a built in pressure relief valve set to 55 to 65 PSI.
It has a brass body and aluminum bonnet.
The inlet is CGA320, while the outlet is a shut-off valve with a 3/8" OD barb.