The pressing device presses the retractable unit toward {TAIL ~ the open position} in which {HEAD ~ the unit} is extended 
The pressing device presses the retractable unit toward { TAIL ~ the open position } in which { HEAD ~ the unit } is extended
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL REL OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL