Large and small cannisters are provided at {TAIL ~ the respective ends} of {HEAD ~ a pivotable frame} 
Large and small cannisters are provided at { TAIL ~ the respective ends } of { HEAD ~ a pivotable frame }
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD