ITEM NAME:DC 12V 2-Channel Relay Module with Optocoupler H/L Level Triger for Arduino A3V7 DC 12V 2-Channel Relay Module with Optocoupler H/L Level Triger for Arduino A3V7 Relay outputs: NO: normally open relay interface COM: Common Interface Relays NC: normally closed relay interface material: metal Module description: the module uses genuine quality relay, normally open interfaces Maximum load: AC 250V/10A, DC 30V/10A; using SMD optocoupler isolation, driving ability, stable performance; trigger current 5mA; the module Operating voltage 12V; the module can be high or low by a jumper setting trigger; fault-tolerant design, even if the control line is broken, the relay will not operate; the power indicator (green), the relay status indicator (red) the interface design of human nature, all interfaces are available through a direct connection terminal leads, very convenient module size: 50mm*40mm*17mm (L*W*H) Module interface: DC+: positive power supply (VCC) DC-: negative power supply (GND) IN: can be high or low level control relay S1,SHighT OR LOW LEVER High and low level trigger options: It is low level trigger when jumper connect to LOW pin It is high level trigger when jumper connect to HIGH pin Package: 1*12V 2CH relay module Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.