I've had one of these for years and it is an awesome device. So easy to raise and lower. This model extends the keyboard tray over the edge of your desk and lowers it below the desktop so it is more ergonomic when you sit. When standing, it positions the keyboard so your arms bend at a perfect 90 degrees...very comfortable. I recommend adding an anti-fatigue pad to stand on.
Very nice and sturdy Standing Desk. It was easy to assemble, I was able to mount two 24” monitors and it is very easy to use. The extra shelf is extremely handy.