{HEAD ~ An axial elongate gallery} 72 is formed on {TAIL ~ the outer surface} 58 extending substantially between the first and second grooves 64, 68 
is formed on
{ HEAD ~ An axial elongate gallery } 72 is formed on { TAIL ~ the outer surface } 58 extending substantially between the first and second grooves 64 , 68
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH