That is a Global VR Pup Cabinet.
Most were outfitted with a 29" VGA monitor, usually the Kortek KT-2938 (Happ rebranded them as well, but I can't remember their model number).
The cabinet was pretty much made to be a MAME cab--VGA monitor, Happ Controls keyboard encoder, audio amp, etc. When it's stock as a Beach Head, you can pretty much just drop a PC in there and be good to go.