Two collars are connected to {TAIL ~ two distal ends} of the two end caps and two ends of {HEAD ~ the casing} 
Two collars are connected to { TAIL ~ two distal ends } of the two end caps and two ends of { HEAD ~ the casing }
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD