Chinook Base Cup Kit
This is just the top piece of a windsurfing mast base that fits with US Cup (2 pin style) extensions. If you need to build a mast foot for your older style board, or make your older mast foot work with a newer Chinook extension, this is the part that you need. It comes with everything you need to attach a US Cup to a rubber universal joint. This will not work with a tendon style base.