Does anyone have any of the old style US Box fins in good condition that they'd be happy to part with? My wife and I got back into windsurfing a few months ago after a break of 20 years and have decided that we're so comfortable riding our old school boards (Bic Metal Rock, Astro Rock) that we're going to stick with them while we get some fitness and skills before upgrading, but we are short on fins.

US Box fins date back 20+ years ago and were used on many boards such as the Bic Rock series, prior to the introduction of bolt-through fins such as the Powerbox. They are the ones that have the horizontal pins that you slide into the fin track, so you can adjust the fin position (although I have no idea what is the best position!) then you screw a small bolt through a hole in the front tab of the fin and into a flat threaded nut that you also slide into the fin track. (see pics).

I also have one fin pictured below that is OK but is missing one countersunk insert bolt for the front tab ... any idea where I could get one?