A wobbly mouse wheel that rattles, especially when scrolling fast and feels like it's about to end. Feels like out of the box from the wheel of the new mouse such as from the wheel of those old mice where the wheel was already dying. I had to drip oil from the trimmer. It always helped to extend the life of the wheel and it got better, plus it developed a little over time, but the rattling did not go away. But as I understand it for Razeir mice, this is, as they say, the norm. Moreover, if you press the wheel a little to the left or right, or press it, then the rattling disappears no matter how you turn it. In general, the wheel does not rattle in all positions except the default - how it happened, there is a great mystery. Plastic, though pleasant to the touch, is easy to scratch with a fingernail. It will not be particularly visible, but the trace will remain when you remove the cover, say. There is no backlight. Personally, I don't care, for someone it's a plus, for someone it's a minus. For example, Bloody still likes to make mice with non-switchable backlight. Well, with backlight it would be harder. On the other hand, it would be easier to search in the dark if it would be important to someone.