This mouse has "only" three buttons. I only put in quotes because it is precisely the reason for my purchase. For me a mouse should be simple to use and 3 buttons + a scroll wheel are enough (and I have the keyboard to do complicated stuff). This mouse works perfectly either in windows or linux (with some features less linux). 2 sensitivity adjustment buttons under the mouse, a resolution of crazy and amazing reactivity make me the perfect mouse (and cheap bonus)