SMAKN&reg; 1-Channel Duplex Signal Relay Module 12V 1A High Level Trigger Power supply: 12V DC. Using original Falco HK19F type duplex signal relay. The input trigger only way, but there are two switch outputs. The output of the relay have two common, normally open, normally closed end, and the two independent work. High-quality high-temperature PA terminals, quality is excellent.