Mount-It! Keyboard Drawer Under Desk with Mouse Platform, Easy-Glide Sliding Under-Counter Computer Keyboard Tray 21 inch Wide

Very easy to put together. Instructions are simple but concise. The makers must assume, however, that you are able to flip over the desk or table you intend to install it on. In our case, that would have been an impossible task. So began several grueling hours of myself kneeling and holding up the keyboard underneath the desk, and my companion lying underneath the desk, attempting to screw in the pieces. The ordeal was worth every agonizing moment of knee and neck pain. The keyboard tray works perfectly, smoothly sliding out from its rails and the mouse tray slides out easily from the side. An excellent purchase.