Air Regulator series ARG is modular style with built-in pressure gauge, offers an optional, built-in backflow mechanism which enables reliable discharge of air pressure from outlet to inlet.  The mounting angle of the pressure gauge is selectable depending on the piping direction, and with the anti-revolving mechanism (PAT.PEND.), the pressure gauge will not be revolved even after the handle is operated.  "Note that the ARG-B has been released as a replacement for the ARG.  While the ARG is still supported with inventory and no obsolescence date has been announced, we strongly encourage the use of the ARG-B for new applications"