I'm selling this because I haven't used it much. I've stored it for a few years, but I've hardly used it. The box has some stains. Brand: ELECOM Color: Black Connectivity Technology: USB, 2.4 GHz Wireless Special Feature: Silent Buttons Movement Detection Technology: Optical Number of Buttons: 5 This wireless mobile trackball "bitra" is designed for index finger operation, achieving high operability despite its compact design, perfect for mobile use. [Connection Method] 2.4 GHz Wireless (Receiver included) [Number of Buttons] 5 buttons *Including wheel button [Size] S size: Width 61.9mm x Depth 93.9mm x Height 40.2mm [Power Supply] One AA alkaline battery, AA manganese battery, or AA nickel-metal hydride battery (Estimated battery life: approximately 110 days)