wherein {HEAD ~ the tip portion} is spaced from the tip wall to provide a leakage path between the annular groove and {TAIL ~ the second check end} 
wherein { HEAD ~ the tip portion } is spaced from the tip wall to provide a leakage path between the annular groove and { TAIL ~ the second check end }
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL