The body of lead may be fixed relative to the outer jacket and the shaft has a portion of {HEAD ~ reduced diameter} which moves through {TAIL ~ the lead} 
The body of lead may be fixed relative to the outer jacket and the shaft has a portion of { HEAD ~ reduced diameter } which moves through { TAIL ~ the lead }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL