{HEAD ~ A spring} on {TAIL ~ the other end} of the collette presses the collette against the shell to produce wiping contacts at the opening 
on
{ HEAD ~ A spring } on { TAIL ~ the other end } of the collette presses the collette against the shell to produce wiping contacts at the opening
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH