More preferably, the valve member is in {TAIL ~ the form} of {HEAD ~ a generally resilient annular ring} 
More preferably , the valve member is in { TAIL ~ the form } of { HEAD ~ a generally resilient annular ring }
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD