This part adds additional capacity to your Boone docking station and allows you to carry more than just 2 inch accessories. They install just the same as your original Boone dock blocks. First you install your c-clip on one side. You slide the pin through and fasten the other side with a c-clip. There you have it. This accessory will hold any 1-1/4 bike rack, ball mount, or cargo carrier. This is part number BH91200, the Boone Dock 1-1/4 inch dock block kit.