The Logitech Trackman Marble Trackball Wired USB Mouse T-BC21 is a versatile mouse designed for convenient use. With its optical tracking method and maximum DPI of 300, it provides precise and smooth cursor movement. This mouse features a thumb button for added functionality and comes in a sleek gray color. It is a reliable option for those looking for a comfortable and efficient trackball mouse, offering connectivity via PS/2 or USB for ease of use.