The LX Sit-Stand Wall Mount Keyboard Arm from Ergotron helps you to position your keyboard for maximum comfort and productivity whether sitting or standing. It attaches to sturdy vertical surfaces or wall tracks via a bracket (97-091, sold separately), while providing vertical and side-to-side motion. Constant Force lift-and-pivot motion technology allows you to position your keyboard with just a light touch. The arm extends the keyboard tray up to 42" and you can also adjust height up to 20". It folds straight up at 90° to protrude just 5.8" from the wall. The ergonomic back-tilt keyboard tray ensures wrists remain in a neutral position during data entry to avoid repetitive-stress injuries while increasing comfort and productivity. Fasteners for direct attachment to wood and metal studs or concrete surface are not included.