LARGE-SIZE COMFORT – Optimal comfort for either hand with a contoured shape designed to follow the natural curve of large hands. Buttons scooping guides fingers into ideal placement. LAG-FREE WIRELESS CONNECTION – Work wirelessly and move freely – from up to 10 meters away – with virtually no delays or dropouts. No cable means no clutter on your desk and easy transporting UNCOMPROMISED QUALITY – Get great quality with precision tracking and accurate line-by-line scrolling at an affordable price. Easier navigation with no annoying missed clicks BUILT TO LAST – Durable and reliable quality from the #1 world leader in mice and keyboards. An everyday computer mouse you can depend on for a longer time 18-MONTH BATTERY LIFE – Enjoy months of worry-free usage. Power-saving mode automatically kicks in when you're not using the mouse to save power. AA Battery Included