A retainer 1 wherein {HEAD ~ said entering nose portion} has a rounded exterior surface and {TAIL ~ an inner enlargement} 
has
A retainer 1 wherein { HEAD ~ said entering nose portion } has a rounded exterior surface and { TAIL ~ an inner enlargement }
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL