The backframe can be switched from a fully extended position under normal use, or {HEAD ~ a collapsible position} under a transportation or {TAIL ~ storage} 
The backframe can be switched from a fully extended position under normal use , or { HEAD ~ a collapsible position } under a transportation or { TAIL ~ storage }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH TAIL TAIL TAIL TAIL TAIL