It performs all functions perfectly. The 4/5 buttons on the right side perform the exact same function as the left ones, you cannot assign them different functions from the left ones. So basically it contains 2 extra buttons than a simple mouse. Besides that, it is excellent. The battery lasts for 1 week with office use and without lights. Lightweight and comfortable.

Well, regarding what has been mentioned by many people about the mouse wheel, it is not true that it is broken. There is a program on the company's website that allows you to change several things (it is not the best program that gives you many options but it is something rather than nothing). From there, you can change the "intensity" of the mouse wheel (the factory intensity is indeed very poor), the color profiles (without having anything ideal like a specific color or changing with the battery percentage), and several other things. It is not something special but for 10 euros it is a quite good and durable mouse. The program definitely needs work and more options, but the mouse also needs some things (for example, a different type of plastic because it slips like crazy if your palm sweats).

So, two months of use and we start with the problems that it ALREADY had from the first day.
1. When you scroll down, there is ALWAYS a "staircase" that sends you 50 "stairs" down. Always though. Okay, I overlook it accepting that the mouse is by default problematic (first fail).
2. The left click, if you don't hold it firmly pressed (e.g. when selecting text and slowly moving downwards), loses contact on its own. The switch does not make good contact, right? (second fail)
3. Many times, the left click falls into empty space (it catches with the second one, okay).

On the positive side:
It is fantastic for LED lighting.

Update a while later: This is an epic fail as a product. There is no correlation between the actual value of the product and its commercial value. Today, it was simply replaced with a much better one for almost the same amount of money, which will definitely do what it was designed for and will not just be a handheld LED light.

Nice mouse overall, but it has a faulty scroll wheel. I received two mice and they had the same issue. It doesn't have smooth scrolling. Occasionally, with a slight movement of the scroll wheel, it abruptly changes two to three pages.