Feature: Advanced ergonomics design to reduce the fatigue of the hand and the pressure of the mouse on wrist. Well-designed thumb spoon to help maintain the correct wrist position. There are forward and back buttons for faster navigation. Three-levels speed regulation, more practical and convenient. Exquisite workmanship and elegant appearance. Specification: Material: ABS Color: Black Compatible: for MAC OS/LINUX/WINDOWS XP/VISTA/7/8 Battery: 2 sections 3a battery(not included) Package List: 1 * Mouse 1 * Receiver Note: Please note that the battery is not included.1Advanced ergonomics design to reduce the fatigue of the hand and the pressure of the mouse on wrist. 2Well-designed thumb spoon to help maintain the correct wrist position. 3There are forward and back buttons for faster navigation. 4Three-levels speed regulation, more practical and convenient. 5Exquisite workmanship and elegant appearance.