This controller enables automation of your dust extraction system, giving more convenient working and saving both electricity and heat (when venting externally). Sensors are attached to each motor and then connected into the controller. The sensors detect the magnetic field generated when a machine's motor is switched on and the dust extractor is then automatically started. The controller can connect up to five machines but, by adding Auto-Expand units, any number of machines can be added. Each Auto-Expand unit will accommodate an additional five motors. The Auto-Extract controller is available in 230V 1ph 13A or 16A. These units operate the extractor directly, you will need to bypass the original switch system. Sensors are available separately, depending on the length of cable required. Additional accessories include a Sensor Switch which allows a machine sensor to be disabled when dust extraction is not always required on a particular machine. Made in Axminster with UK sourced components. NB: A sensor cable is not supplied and will need to be purchased separately. Not suitable for extraction units fitted with automatic filter cleaning systems.-bg