TinyMouse is half the size of a standard mouse and features two distinguishing colors for right-click and left-click and a scroll wheel. Compatible with Windows 98SE, 2000, ME, XP, Vista, and MAC OS 10.1.5 and higher. TinyMouse is about half the size of a standard computer mouse and just right for your child's small hands. A scroll wheel and colored right and left buttons help kids learn to click and move the cursor with greater comfort and control. And with optical tracking, there is no trackball to become dirty, lost, or malfunction.