Wireless trackball M570 with 400dpi resolution. Work in comfort with a stable, sculpted trackball that supports your hand and lets you rest your arm. Unifying receiver the tiny, wireless receiver that stays in laptop and lets you add compatible devices as you need them. With up to 18 months of use from a single AA, you might just forget your trackball uses batteries at all. Trackball stays in one place, so you do not have to move your arm to move cursor. Its sculpted shape supports your hand to let you work all day in comfort. We have refined its proven shape to create the M570. Reliability of a cord with cordless convenience and freedom fast data transmission and virtually no delays or dropouts. The robust wireless connection lets you control your laptop, desktop computer or home theater PC from up to 30ft (10m) away. It is so small it can stay plugged in a USB port. You do not have to unplug it when you move around or worry about losing it. Trackball is always ready to use. Easily connect up to six compatible wireless devices, keyboards, number pads or mice without the hassle of multiple receivers filling up USB ports. If you do need to remove the tiny receiver, just tuck it away right next to the battery. The long battery life virtually eliminates the hassle of changing batteries. The on/off button saves power. You get precise cursor control wherever you want to use your trackball. Hard tables, comfy sofas and lumpy beds are all no problem for the M570. The M570 now sports an adjustable laser sensor, giving a wider range of cursor speed and the perfect amount of control. Can easily move up and down through Web pages and long documents. You can customize your trackball’s buttons to help you do what you want faster. Moving quickly between documents or browsing your favorite Web sites is a breeze with large, easy to reach back/forward buttons. Trackball is easy to take with you around the home. The ball even stays in place when you turn it upside down.