{HEAD ~ The plug} is forced against {TAIL ~ the axial valve seat} when the valve is closed to deform in both axial and radial directions 
is forced against
{ HEAD ~ The plug } is forced against { TAIL ~ the axial valve seat } when the valve is closed to deform in both axial and radial directions
HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH