...energy efficient wireless optical Mouse. The used infrared sensor reducing drive voltage and allowing the mouse to function at a lower power consumption level. Using only one AA battery, you can use the mouse for up to 18 months*. Rely on the power indicator to tell you when it’s time to replace the battery.NX-6550 provides quick and easy access to Windows 8 features. Quickly navigate to switch to the Windows 8 Metro interface.NX-6550 has a convenient battery compartment design that fits either an AA or AAA battery and a power switch is added to extend the battery life. The rubber hand grip design on the sides provides comfort and ease of use.