It's a locking retention ring where the flat end sticking out rests in a groove, BUT... I can't remember what the heck it comes off of. I can see the connector clearly in my mind but it's been years since I've put one back together. Basically it's holding a shaft in place on a wachamacallit. I have one buried in the garage somewhere, my dad kept everything... lol or I should say he keeps everything thinking he might use that $.10 cent item sometime in the next 100 years that great gramps had sitting here for another 50 years before dad inherited it. Man he gets sure torched when he sees me ordering a dumpster now a days after the last fiasco when my sis & I filled an 80yarder when he was out of town... lol
