Watt balance machine, inner workings close up, at the National Institute of Standards and Technology, Gaithersburg, USA - stock video

Close up shot of the Watt Balance machine's inner workings at the National Institute of Standards and Technology, Gaithersburg. It is an experimental electromechanical weight measuring instrument that measures the weight of a test object very precisely by the strength of an electric current and a voltage. It is being used to try and redefine the kilogram.