A really slick, strong bracket for attaching and easily adjusting the height of anchor chains. One chain can easily be dropped over the top so that the links fall in the slots. Alternatively either one or two chains can be passed up through the tube and then their links slotted into either/both slots at the top.
This bracket mounts flush to the dock frame boards either on the inside or outside of the frame. As such it doesn't hang down below the dock and create a head hazzard for swimmers coming up from below the water surface.