The formed welded unit may then be placed in a mold that consists of two halves to facilitate formation of {TAIL ~ an internal flexible membrane} that defines part of {HEAD ~ the valve} 
The formed welded unit may then be placed in a mold that consists of two halves to facilitate formation of { TAIL ~ an internal flexible membrane } that defines part of { HEAD ~ the valve }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD