A second form of {HEAD ~ the apparatus} provides for {TAIL ~ a pair} of conductors not in mutual contact but each in contact with the test contact member when the latter is in the rest position 
A second form of { HEAD ~ the apparatus } provides for { TAIL ~ a pair } of conductors not in mutual contact but each in contact with the test contact member when the latter is in the rest position
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH