The top half of the control unit contains mouse movement arrows with two buttons on each side, as well as 8 buttons on the top. The buttons at the top are mostly for optional components, such as an answering machine on the computer (Message button) and control over 3-D Amphitheatre Stereo Sound (SRS button). The mouse movement arrows are most likely my favorite feature in this model. There are two buttons on each side of the center circle, the one on the left is for simulating a left click, and the one on the right is for right clicks. Of course, you can configure them to do other tasks, but being placed so near to the mouse buttons, having them act as mouse buttons is pretty logical.