... 2.Working voltage : DC12V 4-channel wireless remote control switch with wireless transmitter KL-K400C Specification & user manualTechnical ... modelPress remote button A, the receiver relay A is on, the relay B/C/D is off.Press remote ... button B, the receiver relay B is on, the relay A/C/D is off.Press ... remote button C, the receiver relay C is on, the relay A/B/D is offPress remote ...