Chester Mouse is a Green one-button computer mouse...Young children can be confused about whether to use the right or left button on a mouse, and clicking on small objects, using drag-and-drop and click-and-move can be frustrating. A standard mouse doesn't fit into small hands or the buttons are just too far apart. Welcome Chester, a tiny single-button mouse with no scroll wheel, that's easy to control and made of rugged plastic for strength and durability. Size: 3.38" long x 2.25" wide x 1.25" high; 1 button (left click); 800 dpi Optical Tracking; USB with PS/2 adapter included; Compatibility: Windows 98SE, 2000, ME, XP, Vista, MAC OS 10.1.5 and higher; FCC CE Approved, RoHS Compliant; Mac compatible.