The keyboard and mouse tray does what it says it does.
It's a little tricky to work out which way it goes as the mount at bottom of the tray is not centred. The pivot capability is there but not ideal with the tightening handle in the way on the bottom of the stand, so it hits the upright to the steering mount. The pivot motion is not very smooth and is a little wobbly.
Having said that, If you are buying this, you should not be using it to type out essays, it's meant to occasionally use the keyboard and mouse within racing game menus. So it's fit for purpose and allows easy access to these devices without them having to be put on your lap or a side table as I was doing.