The unique QuickShift™ donut has been designed to be the most universal and flexible mount for common pole diameters and the easiest to install. The SD-DO features the QuickShift™ lever which allows you to quickly and freely move and lock the display along a pole without using any tools. This product readily adapts to poles 1.65in and 2inin diameter. The QuickShift™ donut utilizes a ball joint to offer easy, infinite display adjustment for any viewing angle range up to 20 degrees in any direction. Even after the screen has been installed, it''s easy to change position from landscape to portrait and then securely lock into position. The built-in quick release mechanism ensures hassle-free, secure removal or replacement of the display.