The two longitudinal members 12 and 14 are each formed of sections of hollow cylindrical metal pipe or tube, such as EMT or other reasonably light weight and suitable material of {HEAD ~ sufficient strength} for {TAIL ~ the purpose} 
for
The two longitudinal members 12 and 14 are each formed of sections of hollow cylindrical metal pipe or tube , such as EMT or other reasonably light weight and suitable material of { HEAD ~ sufficient strength } for { TAIL ~ the purpose }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL