{HEAD ~ A third form} of the apparatus includes {TAIL ~ a pair} of conductors not in mutual contact, but each in contact with a third conductive member when in its rest position 
includes
{ HEAD ~ A third form } of the apparatus includes { TAIL ~ a pair } of conductors not in mutual contact , but each in contact with a third conductive member when in its rest position
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL 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