There is a link on that site that show it works with round magnets they call MAGs at the bottom that are customizable to put adds on them and shit. Then they can be used as frig magnets and shit after you down the beer. They like some old school pog looking things.
Its impressive how the tap knows when to stop filling up the beer when its near the top. So I think its pressurized and a sensor is programmed to stop filling when it becomes a certain weight.