Advanced 2.4 GHz wireless: A 2.4 GHz wireless connection means you can work or play in more places. The long-range connection virtually eliminates delays, dropouts, and interference. Unifying Receiver: The tiny USB wireless receiver stays in your laptop, so there’s no need to unplug it when you move around and connects both the keyboard and mouse. Full size functionality: Have the functionality of a full-size keyboard without sacrificing form or function. The MK520 includes a stylish and streamlined keyboard and ambidextrous mouse Long-Term Battery Life: The MK520 package boasts significant battery run time. Using 3 regular batteries, the keyboard will last for up to 3 years, and the mouse for up to 18 months Simple setup: Simply plug the Logitech Unifying receiver into your computer and you’re ready to work—nothing else is needed Encrypted connection:  Enjoy the flexibility of working wireless with an encrypted connection. The MK520 utilizes 128-bit AES encryption and a 2.4GHz signal to keep your connection fast and secure