Expert Mouse Wireless Trackball gives you the freedom to be hyper-productive without being limited by a USB cable. The trackball can be paired through Bluetooth 4.0 LE to save a valuable USB port, or connected via USB nano receiver. TrackballWorks software offers incredible customization. Optical tracking technology offers smooth, precise cursor control. Award-winning Scroll Ring lets you quickly scan up and down web pages or long documents. Add it all up and you get exceptional comfort and ease-of-use from the brand that has set the industry standard in trackballs for more than 20 years. Detachable wrist rest for hand and wrist provides ergonomic comfort. Amofferextrous design works equally well for both right-handed and left-handed users. Auto-sleep helps conserve AA battery life.Kensington Expert Mouse Wireless Trackball, Black