This is a part that upgrades your Boone docking station to take Yakima and Thule racks, and virtually any other rack that uses a threaded fitting instead of a hitch pin. What this pin does is replace the original pin on the Boone docking station. Basically you just unclip these clips, pop off the one side and re-install with the new clips. This way you can install your threaded side out of your bicycle rack onto your pin. We will replace the bottom one and show you how it works. We need to remove one of the c-clips and hold one edge of it, take a screwdriver and flip it up a bit. Once you get it started, get to the middle and put your screwdriver underneath it and slide it up with your finger so it does not fly off. Now re-assemble your dock block insert your new pin and make sure it is in correct orientation with the threads on your bicycle rack. You have to make sure because the threads are on the outside edge or else it will not fit on. Once you have it right, you can put your c-clip back on. We will now install the bicycle rack with the threaded fitting. Just to give the point of view, we will just point out that the threads are on this side of the shank. To show you how it works, look down there and see it is open and the pin goes through. One other thing about this is that one half you can use for your bicycle rack while the other half is open for any two inch accessories. There you have it for part # BH83747, the Boone dock cross pin for Thule and Yakima bicycle racks.