This is a Logitech M570 trackball mouse, a classic model. The left and right click buttons have been replaced with silent buttons. You won't have to worry about the clicking sound in an office environment. I guarantee the functionality for one week after purchase. It's in good condition as it hasn't been used much. It works perfectly fine in my environment. It supports Unifying, so you can pair it with your existing receiver. If you need a receiver, I can include one for an additional 700 yen. Logicool Wireless Trackball M570 Brand: Logicool Mouse/Trackball Type: Trackball Cable Type: Wireless Connectivity: Wireless (2.4GHz) Number of Buttons: 5.0 buttons Optical Resolution (dpi): 400.0 dpi Color: Gray / Blue Battery Type: AA