This is brand new commercial electrode steam humidifier, not for resident application. All units are 3-phase AC, 110V, 230V, 380V, 440, 580V are available. It uses tap water, don"t need any water pre-treatment system. It has a micro-processing controller, which ensures a reliable and accurate operation. Possible for on/off control and proportional control, 0-10V, 4-20mA, 0-1V, 0-5V, 2-10V, 0-20mA signals are accepted. It is easy to install, just follow the installation, operation and maintainance manual.