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