The wheel in the middle is bad. There is friction while rotating it. It seem to get stuck and then moves suddenly. No linear motion while scrolling pages using the wheel. I am very surprised by the poor quality of the wheel rotation, It is heart breaking considering it has good company name of "Toshiba". I will request customer service to process returning this mouse & hope they improve the wheel mechanism in the mouse in the future. I am sorry for this review because of bad wheel. The buttons work fine.