The unique Quick Shift 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 Quick Shift lever which allows you to quickly move and lock the display freely along a pole without using any tools. The product readily adapts to poles 42mm and 50mm in diameter. The Quick Shift Donut utilizes a ball joint that allows infinite and easy display adjustment for any viewing angle range up to 20 degrees in any direction. Even after the screen has been installed, it is easy to change its position from landscape to portrait and can then be securely locked into position.