The spring is biased to require {HEAD ~ sufficient force} to insert or remove {TAIL ~ the ferrule} 
The spring is biased to require { HEAD ~ sufficient force } to insert or remove { TAIL ~ the ferrule }
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL