Compares with the traditional mechanical relay, the Solid State Relay (SSR) has many advantages: it has a longer life, with a much higher turn on/off speed and no noise. Besides, it also has better resistance to vibration and mechanical shock, and better moisture proof performance. This Solid State Relay Module is based on Omron G3MB, controls current upto 2A@240VAC, and can be widely used in various areas such as computer peripheral interfaces, temperature/speed light adjustment, servo control, petrochemical, medical instrumentations, financial devices, coal, meters, traffic signals, etc. There are also modules with 2 channels and 4 channels for your choice. Technical Details: Control Voltage: 5V Static Current: 0mA Working Current: 12.5mA Trigger Voltage: 0-1.5V Trigger Current: 2mA Instructions: DC+:Connect power positive DC-:Connect power negative CH:Relay module signal trigger end (Low level trigger is effective) Wiring: When the triggered by low voltage, current will get through