The desk I ordered from Wayfair didn't come with the correct part for the installation of the keyboard tray. Thankfully, this was available for purchase and this is the PERFECT part for what I needed to install the keyboard tray. I shouldn't have had to purchase this at all, but since the packaging for the desk and all its parts didn't contain the correct part for the keyboard tray, this did the job nicely.

I purchased these because the rails that came with my desk literally pulled apart and the bearings fell all over the floor, they were cheap generics. I had to modify the desk as the original mounting hardware was welded in but these had the most options when it came to installing. You can adjust the height, the direction the mounting flanges attach to the rails and it enabled me to remove the old hardware and install these in place and reuse everything else from the desk. Including the metal and glass keyboard tray. item is exactly as shown in the amazon description. Came with screws that I was able to use even with the metal desk. I am super happy with my purchase. I can finally rest my hands on my wrist rest without fear of it breaking off the desk. I bought 16 inch size which turned out perfect, they are exactly 16 inches long, they have 10 inches of travel.

The only downside has nothing to do with the slides and more of a desk complaint. There was limited space where I could attach the mounting hardware to the desk and you cannot relocate the mounts on the rails as those points are fixed so the tray slides a couple inches past the front edge of the desk which in turn does limit how far out the tray can slide out. It is a mix of desk limitations with the inability to move the mounting points along the rail. Other than that I have no other complaints.

Overall if I needed to add a tray to another desk I would definitely buy these again and recommend these to anyone reading this.

I used a 3/4 inch piece of pine board to make a keyboard tray with these rollers. It rolls fairly smoothly, and it will lock in the extended position so that it wont move while you type/work. Despite being firmly affixed to my desk, the connecting brackets allow for enough flex that you must close the tray with both hands on either side when it is fully extended in the "locked" position. Otherwise, it will flex and seize up temporarily. Once you get used to it, it works well, and I see no reason it shouldn't last a long time.

I mounted a full size 52 inch width Casio electric piano under a 60 inch desk. I purchased two black metal shelf support rails from Home Depot and cut them down to size for the span/platform. I also had to use bolts, nuts, and spacers to lower the keyboard platform just a bit for 4.5 inch clearance. Some reviews complain the height has limited adjustment. I knew this job would require good planning and modifications for my install. I'm now very happy to have my piano under my desk and not taking up real estate in my home, and it looks good.

Full disclosure, I've only had this installed for about 10 minutes now. So far, they work and seem to be a significant improvement to the clamp option.

I had been using a keyboard tray that clamped onto the desk. After years of that swimming and shifting each time the tray was pulled out or pushed in, I finally decided that (with a wooden desk) I should invest in something more permanent. I settled on the 12-inch length because that is how long my keyboard tray is. I also settled on these because I could easily retrofit my current keyboard tray to use these. After installation, however, I feel I should have gone with a longer set in the hopes of more fully hiding the keyboard tray under the desk. To get a sufficient extension, I determined (by eyeballing it) that the tray will have to stick out from under the desk by about .5-1 inches. Not appealing, but better for when typing though I have no real proof whether longer brackets would have solved this issue or not.

How much room you have under the desk will likely determine how easy these are to install. That and the weight of your keyboard tray... Admittedly my tray is quite a bit heavier than probably necessary (bamboo board). So it's reasonably easy to put together, but I struggled because of the weight of the tray and the space available under the desk to attach these.

The sliding mechanism seems functional enough. Feels fluid and locks in the in or out position sufficiently. I'm not going to assume that I got the brackets attached to the underside of my desk in perfect alignment, but so far, there doesn't seem to be too much play once all 8 screws are in place. And I don't imagine there are many solutions for avoiding this other than perhaps thicker brackets (honestly, the arm brackets attached to the desk's underside are quite thin).