The components which define {HEAD ~ the three points} of {TAIL ~ engagement} with the test member are mounted on this frame 
The components which define { HEAD ~ the three points } of { TAIL ~ engagement } with the test member are mounted on this frame
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH