Logitech's most advanced trackball for trackball enthusiasts and consumers searching for alternatives to mice and touchpads. Delivers 20% less muscular strain compared to a regular mouse. MX ERGO features a unique adjustable hinge for personalized comfort and the latest tracking, scrolling and power management technology. Logitech FLOW enables effortless cross computer control. Finally a trackball you can truly call your own. A unique adjustable hinge allows you to choose the best angle between 0°and 20° for a more natural hand position and greater comfort. Change the speed and accuracy of your cursor for optimal control with a press of a button. Get things done faster with quick access to shortcuts. The precision scroll wheel features horizontal scrolling and a convenient middle click. Connect and work on two devices at the same time and easily switch between them. Boost your cross-computer experience with Logitech FLOW technology. Copy and paste text, images and files between computers. Battery holds power for up to 4 months on a full charge. One minute of charge gives up to a full day of use.