Sail Track Stop or...
I will take a crack at this. I am assuming that you may be looking for a Sail Track Stop of some sort that prevents your sail slugs from coming out of the sail track when you lower or reef the sail. There are two types that I have used: one is an actual sail track stop that slides into the sail track and then tightens down by tighening the knob. These are available through West Marine...and probably Rudy at D and R Marine. On our O'Day 28 (Isomat mast) we don't have the Sail Track Stop, but instead we have a stainless pin that looks like a Clevis Pin with a small ball-bearing at the butt end, which we insert into a hole that is drilled right next to the sail track. The ball-bearing prevents the pin from sliding back out once it is inserted. The pin has a short tether that is attached to the mast a few inches starboard of the hole so that when you remove the pin it just hangs there. I don't know the technical name for the pin...but I had to get a new one this year and was able to find it in a local marine store. These pins are normally 1/4 inch diameter. Hopefully this is what you were looking for!
