Mick, Dirk, Yep, it;s a nylock, exactly asd TG describes.
TG, yep, sealed bearings too which I also was a little gobsmacked about but seem to have survived goodness how many swims & miles. (I'll need to go check my trip log & do some maths with a route planner).
Loks like I've just turned ribnet theory on it's head!
So, TG, how much for a pair? (the rest of that conversation might be a PM moment!