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