The EFD will move up and down over 14″ to get the most comfortable sitting and standing positions. The entire unit (including the keyboard tray and monitor) easily moves up and down with the gas-spring arm. The monitor height can be adjusted separately for the optimal ergonomic position. The monitor mount will hold up to a 27″ monitor. The EFD gives you the best of both worlds. You can sit part of the day, as you always have, but you can also stand and take advantage of all the health benefits that come with standing and moving around. You and your associates will be healthier and more productive. Your EFD mounts to your current desk or credenza. The tray can be folded up and the EFD can easily be swung out of the way when you want to use your desk. It includes clamp and grommet brackets to work with most desks and credenzas. With the EFD+2 accessory kit, you can hold 2 monitors, up to 24″ each. The large 26.5″ x 9″ keyboard tray will hold your keyboard and mouse. With the EFD-T accessory kit, you get an extra tray to hold your notes for typing, phone, calculator, pad, pens, etc. The EFD will hold up to 24 lbs. (total weight, including monitor(s), keyboard and accessories).