This is a review of the keyboard tray that's described on the Amazon page as "Color: Under Desk" with 5.5 inches of vertical span, rather than the "Color: Black" keyboard tray for use with a standing desk that has 13.4 inches of vertical range.Because of space constraints, I had to modify a benchtop in my home office that's holding my two printers so that it could also be used as a computer desk. This setup is admittedly far from ideal: the benchtop is 17.5 inches deep, had barely 26 inches of free space left to right, and is an awkward 33 inches off the floor -- much too tall for a conventional desk and too short for a standing desk. (I do have a real computer desk, but that already has a computer at it, and there's no room there for a second computer.)This keyboard tray fit my needs perfectly. I mounted a shelf about 4.5 inches underneath the benchtop so that the keyboard tray wouldn't have to extend to its maximum downward reach in order to put the keyboard at a comfortable height. Reviewer Lawes included pictures of a similar shelf in his or her review that was used for a standing desk. Lawes mounted the track so that the keyboard tray slides from left to right, whereas I mounted mine so the tray slides in and out. We used the same shelf configuration, though.The keyboard tray is sturdy -- there's a very tiny bit of wobble, but not enough to affect my typing or even to move the mouse. I didn't use the included wrist wrest. Mounting was fairly easy for a single person. I wouldn't hesitate to get another one of these keyboard trays if the need arose.That said, the product does have a few small downsides. As others have noted, if you mount the front edge of the tray's track flush against the front edge of your desk, the keyboard tray will still stick out about 3 inches past the edge of the desk when you push the tray all the way back. Not a problem in my case, but something you might need to know. Also, it was a little difficult to slide the tray in and out easily, until I applied a small amount of lithium grease to the track. Now the tray moves quite smoothly, but there's still enough friction where there's no way you can "bump it closed" by accident.The thing I was most disappointed in was the absence of a lip on the keyboard tray to keep the keyboard and mouse from sliding off the back side of the tray when you push the tray in or pull it out. If you don't store the keyboard on the stray, this won't be a problem. But I do, and it was, especially before I applied the grease, when movement of the tray was not smooth and required some finagling.I got around that by putting foam shelf liner on the tray underneath the keyboard (but not on the part of the tray where the mouse rests). That stuff really grips and won't let anything slide. I keep my keyboard tray fairly level. I don't know how much tilt you can have on the tray before the shelf liner is no longer effective. As for the mouse, I just tuck that into the little shelf I built under the benchtop before I close or open the tray, and then there's nothing to worry about.