USB-nFOCUS adapter connects your nFOCUS to your PC or MAC, for easy remote operation of your focuser. All the great features of nFOCUS (see above) now available from your computer! Fully ASCOM compliant so it will work with popular focus control programs. Full step size and interval control from computer and display of step count. Computer control , doesn't affect manual operation (doesn't change your favorite nFOCUS manual pulse width/interval settings). USB and nFOCUS cables included. Software and ASCOM drivers for Windows xp/vista/7 and for MAC from stark labs (www.stark-labs.com). Approximately 1.5 inches wide by 4 inches long by 0.5 inches thick.