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