thumb rolling trackball mouse 10M 2.4GHz USB Handheld Wireless Optical scroll ball rollerball wireless Trackball Mice Mouse Off-table design for free and comfortable operation Off-table design for free and comfortable operation It can greatly ease the harm of palm joint or muscle for long time using mouse 2.4GHz Wireless connectivity with working distance within 32ft (10m). Dolphin shape design with left/right clickers, fit left and right handed users. If you have problems, please feel free to contact us. Please do not give us negative feedback, this item bring us few profits.