The shoulder region merges into and provides {HEAD ~ a transition} between {TAIL ~ the finish} and a sidewall portion 
between
The shoulder region merges into and provides { HEAD ~ a transition } between { TAIL ~ the finish } and a sidewall portion
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH