LJController external is based on the Labjack U12 driver (which can be downloaded on labjack.com). This Max/Msp external encapsulate the driver, in order to provide integration in Max/Msp applications, ease of use and advanced functionnalities.
The LabJack U12 is a measurement and automation peripheral that enables the connection of a PC/Mac to the real-world.
Labjack U12 is very convenient to build custom controllers for software, without any soldering (full box version, as in the picture), or to integrate into a hardware equipment (electronic circuit only without box, plugs, ...). It's small size (around 8x12 cm for version without the red cover) allows it to be embeded in small devices.
Important: the Labjack hardware doesn't require separate power supply, it is USB powered.