This product improves on the already good Trackman Marble+ by making it cordless. It offers two buttons plus a clickable wheel in between. The device just simply works and without a cord. I have now installed several at client's and they are all happy with them. The only problem with them so far is that Logitech doesn't offer a keyboard combo with this device, so if you want a cordless desktop you will have two receivers hanging off the back of your computer.