ELECOM Wireless Trackball Mouse - Brand: ELECOM - Model: M-IT11DR - Connectivity: Wireless (2.4GHz) - Number of Buttons: 5 - Trackball Size: Large - Power: AA Battery (1) - Included: Everything included, such as batteries and the box. Reference Price: ¥4,965 (Amazon) This model uses a receiver that plugs into a USB port. I am selling it because I mistakenly purchased it thinking it was a Bluetooth model. Please purchase only if you understand that it has been stored at home.