Take comfort with youThe compact M545 is easy to take with you and is ideal for anyone who prefers a smaller mouse. Back/Forward thumb buttonsMoving quickly through documents or browsing your favorite websites is a breeze with buttons conveniently located under your thumb. Our smallest receiver everOnly 3 mm long, our plug-and-forget pico receiver practically disappears in your USB port. Plus, you can add up to six Unifying devices to it. 18 months battery lifeWith On/Off switch, smart sleep mode and battery life indicator, you might just forget this mouse runs on batteries.