Hoffman VHDPOST, Post Mount Adptr, 5.00X4.00X4.00, Steel/PaintOrder separately when installing the SYSPEND¢ VHD-Motion Arm to a 3.5-in. OD tube.Features:RAL 7035 light-gray polyester powder paint finishIncludes hardware to mount the adapter to the arm and setscrews for mounting to a tube