The clamp plate extension has a concave, circular toothed depression forming {HEAD ~ one half} of a socket to hold {TAIL ~ a ball} 
to hold
The clamp plate extension has a concave , circular toothed depression forming { HEAD ~ one half } of a socket to hold { TAIL ~ a ball }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL