{HEAD ~ The device} may be used to test {TAIL ~ such switches} without affecting the load controlled by the switch 
used to test
{ HEAD ~ The device } may be used to test { TAIL ~ such switches } without affecting the load controlled by the switch
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH