Up to four devices (e.g., monitor, printer, modem) are automatically switched on/off with the main device plugged into the red "master" socket. This means that you don't have to switch devices on/off individually. If consumers are switched on, a red indicator light comes on. In order to adjust the red master socket to the connected master device (main device), you can configure the switching threshold individually (min. 15 W). Integrated surge protection protects the connected devices from surges due to, for example, inductive & capacitive voltage peaks during switching, atmospheric effects & static charges. If surge protection fails, an acoustic warning is given. The additional line filter protects against high-frequency interferences from the mains.