Wave design with Constant Curve layout: Curved layout guides hands into just the right position Ease and comfort: Cushioned palm rest makes work easier and fun more fun Longer battery time: This feature gives you up to three years of battery life. (Battery life based on a calculation of an estimated 2 million keystrokes per year in an office environment. User experience may vary.) Logitech Unifying receiver: The tiny Unifying receiver stays in your notebook, so there's no need to unplug it when you move around. And you can easily add compatible wireless mice and keyboards to the same wireless receiver