{HEAD ~ A filter regulator} filters the air entering the signal air path and regulates {TAIL ~ the pressure} in the signal air path to a predetermined pressure 
regulates
{ HEAD ~ A filter regulator } filters the air entering the signal air path and regulates { TAIL ~ the pressure } in the signal air path to a predetermined pressure
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH