There are 2022 letters in all (the hue is gray, reflecting the English language). The keys can be either round or oval in shape. While the batteries are still working, I continue to use it continuously for three months. In addition to the F1-F12 controls, which are the primary adjustments, there are also keys for modifying things like the volume and the brightness. You have the ability to make the adjustment in Windows. I'm not sure if it can be done on Ubuntu because it doesn't come with any software from the manufacturer. MAC is supported, and there are keys available for it. In general, very excellent quality, however when compared to the MX Keys (which are not compact and are 3.5 times more expensive), the quality of the keystrokes is slightly worse on this product. Is there support for the Logitech Mouse Flow feature, which allows the keyboard to switch to another device while the mouse is still in use? I can't say for sure because I don't make use of that myself.