Sourcingbay New Wireless Trackball Mouse Handheld Wireless Mouse USB 2.0 Mouse Mice With Laser Pointer For Laptop PC Mac Desktop Computer Suitable for Tablet PC Laptop Desktop computer With Laser Pointer. Ideal product for speech and lecture. Powered via one AAA battery (NOT included) Features 3-button design with trackball, Easy to use - left or right hand, or cradled between both FOUR GROUP DPI:400,600,800,100; USB PORT, USB receiver is included It can greatly ease the harm of palm joint or muscle for long time using mouse