Our Cast Aluminum Set-Screw Dock Base is larger than the competitors, offering more stability. The holes on the bottom allow the dock to settle faster, and won't be suctioned to the lake bottom when removing the dock in the fall. Size is 11" on diagonal. Fits 1-1/4" and 1-1/2" I.D. Pipe. The post hole goes all the way through, so you can stick the pipe all the way through and into the lake bottom if desired, to make the posts the same height. This can also be helpful if you need to keep a short dock from sliding down a drop-off or ice ridge.