The instructions could also be better. The standard functions are indeed self-explanatory - if you only need that described above is certainly not a problem. But how can I ask the sentence: "Relays with suitable functions to feed back the switching voltage signal of a dimmer switch." understand? In addition, the relay has two inputs C1 and C2, the only with the words "In addition electrically isolated universal control voltage 8..230V UC." be mentioned. What exactly does this input remains a mystery, and I have tried it yet.