This is a set of two, as they were used at two locations. One has a used feel, but both are in good working order with no problems. For those who really want this, or for stocking up, how about it? Logitech Logitech trackball mouse, wired, gray. - Brand: Logitech - Model: Trackball Mouse - Color: Gray - Features: Trackball - Connection Type: Wired Thank you for viewing.