The valve assembly has {HEAD ~ a two part housing}, one of {TAIL ~ the parts} having a sight glass secured therein 
The valve assembly has { HEAD ~ a two part housing } , one of { TAIL ~ the parts } having a sight glass secured therein
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH