The exterior surface of the ferrule comprises a circumferential ridge and {HEAD ~ groove} that reversibly interacts with a spring inside {TAIL ~ the adapter cavity} 
The exterior surface of the ferrule comprises a circumferential ridge and { HEAD ~ groove } that reversibly interacts with a spring inside { TAIL ~ the adapter cavity }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL