Features If used for conditions of strong interface, it is suggested to connect a diode to input terminal in series, and connect a 470UF capacitor to GND in parallel,More professional and practical. The power supply should be DC12V, but cannot be used for cars because instant voltage of cars may exceed 12V,Stable quality, praised. This is a typical bistable circuit board, press trigger switch to energize relay and press again to dis-energize relay. Designed with screw terminals, it is convenient to wire and easy to use,Simple to install no hassles. Trigger switch connect to trigger signal, trigger signal is low lever effective. Specifications: Power Supply: 12V DC Load Capacity: 10A, 250VAC; 10A, 30VDC Size: 1.5*3.5*4.5cm/0.59*1.38*1.77in Package Includes: 1 x Relay Module Package List