{HEAD ~ means} for detachably mounting {TAIL ~ said hopper box} across the rear of a sand/salt hopper truck 
{ HEAD ~ means } for detachably mounting { TAIL ~ said hopper box } across the rear of a sand / salt hopper truck
HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH