{HEAD ~ The insert} has two arms that each extend from the intersection of {TAIL ~ imaginary extensions} of the secondary locating sides 
{ HEAD ~ The insert } has two arms that each extend from the intersection of { TAIL ~ imaginary extensions } of the secondary locating sides
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH