Very elegant looking tray made from very durable metal material, this is by far the best laptop/tablet/portable desk stand we've had. I had spinal surgery and as a homeschooling parent it didn't happen soon enough but I'm very glad I found and bought it! corners, you will need to wiggle the tray or other adjustable leg angle to allow the locks to return into place. Otherwise it can be quite difficult to get some of the latches back into place when adjusting the legs and tray. We loved it so much we bought one for our son and one for each of our 3 nephews! I didn't want to give up mine! lol! We didn't find it necessary to install a "mouse stand tray" so I can't tell you how it works. It seems pretty easy to install and is a decent size. I checked that this compartment could support the weight of our largest laptop, a very heavy HP. I left it overnight and no problems. Despite being a sturdy tray, it's not heavy at all, making it very easy to pick up. I am small and frail due to back surgery and had no problem moving this tray. I was a bit skeptical about using it prone with the tray hanging over my head. I have the largest iPad Pro with a heavy keyboard case attached. As a result, it weighs more than some laptops and I didn't want to put it on my face. But of course, this tray allows for angles that seem to defy gravity. ! It made me feel like we were approaching the "LAZY WALL-E CHAIR POPULATIONโ! lol! I highly recommend this tray! You will not regret the investment!