{HEAD ~ The front cover} is movably mounted on the base and has a rear surface and {TAIL ~ a transverse slot} formed on the rear surface 
has
{ HEAD ~ The front cover } is movably mounted on the base and has a rear surface and { TAIL ~ a transverse slot } formed on the rear surface
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH