Designed to be mounted on the DIN rail in the breaker box, the Shelly Pro 3EM Switch Add-on offers even greater functionality than the Shelly Pro 3EM devices by offering features like weather-driven energy optimisation like disabling the heating on sunny days, anticipating higher temperatures. The Pro 3EM Switch Add-On can also help balance your PV systems load, such as redirecting excess produced energy into other appliances like water heaters, charging stations for electric vehicles and other energy-intensive appliances to reduce your dependence on the grid. The Pro 3EM Switch Add-on features dry contacts and is DIN-rail mountable. ***Please note: The Pro 3EM Switch Add-On is only compatible with the Shelly Pro 3EM.