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