Logitech MX ERGO - Trackball - optical - 8 buttons - wireless - Bluetooth, 2.4 GHz - USB wireless receiver. 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.