The function of the four changeover contacts is switchable for each individual relay, suitable for momentary or toggle operation, or for switching any remote-controlled devices. The relays therefore either switch only for the duration of the button press or change their state between on and off with each new button signal. The receiver evaluates each radio signal from the compatible transmitters of the SH-12 series, with up to 60 units being learnable. The assignment of the transmitter buttons is already fixed to the four potential-free changeover contacts. Two selectable frequencies (433.62 MHz or 434.22 MHz) and various control LEDs are available. Combined with a special transmission technology, this results in extremely low interference operation, with ranges of up to 1000 m possible. There is also feedback for the transmitted signal to the (handheld) transmitter via an LED. This is a pre-assembled 4-channel receiver in a surface-mounted housing with four relays for connection to 12 - 24V DC and a λ/4 wire antenna.