{HEAD ~ The valve member}, which may be formed from a single piece, may define {TAIL ~ an enlarged portion} retaining the seal and a stem retaining the bias means 
{ HEAD ~ The valve member } , which may be formed from a single piece , may define { TAIL ~ an enlarged portion } retaining the seal and a stem retaining the bias means
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH