Canon DK-1000i II USB Portable Numeric Keypad & Calculator w/Built-in Trackball, Large 12-Digit LCD & Retractable Cord Canon DK-1000i II USB 12-digit Desktop Calculator w/Trackball General Features: Stylish black and silver design Trackball with right and left mouse buttons Scroll wheel PC touch keypad Large 12-digit LCD display PC link function Retractable 34-inch USB cable USB Plug Play technology Tax calculation Dual power source - solar and battery (CR2032 button battery installed)