Based on the best-selling shape in the world, the contoured shape with textured rubber grips keeps your hand happy—even after long hours. The long battery life virtually eliminates the hassle of changing batteries. Smart sleep mode saves power, while an indicator light eliminates surprises. *Battery life may vary based on user and computing conditions.* You pop the tiny Logitech Unifying receiver in your notebook and leave it there. You can even add more devices. Plug it. Forget it. Add to it. You get the reliability of a cord with wireless convenience and freedom—fast data transmission and virtually no delays or dropouts.