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