Logitech M525 Wireless Mouse &ndash; Long 3 Year Battery Life, Ergonomic Shape for Right or Left Hand Use, Micro-Precision Scroll Wheel, and USB Unifying Receiver for Computers and Laptops, Black/Gray ERGONOMIC SHAPE - Ergonomically shaped design and soft rubber grips conform to your hand to be naturally comfortable, and the compact size makes it easy to take with you wherever you use your computerat home, at work, or anywhere else LONG BATTERY LIFE - 3 year battery life and smart sleep mode help you go longer between battery changes CONVENIENT CONTROLS - Easy-to-reach Back/Forward buttons makes moving quickly between documents or browsing your favorite Web sites a breeze MICRO-PRECISE SCROLL WHEEL - With more grooves per millimeter, our new scroll wheel gives you the ultimate navigation experience. PLUG'N'PLAY CONNECTION - Nano-sized Logitech wireless unifying receiver stays in your computer plug it in, forget it, even add compatible wireless devices without multiple USB receivers