It is 4 Channel Isolated 24V 10A Relay Module, each relay can individually switch on/off by an -isolated digital input, Standard interface can be directly connected with microcontrollers and be controlled directly by a wide range of microcontrollers such as for , AVR, PIC, ARM, , etc. very convenient. Equipped with high-current relay, maximum load: AC250V 10A, 15A 125VAC, DC30V 10A; Trigger current of -isolator: 5mA. RELIABLE: Fault-tolerant design, even if the control line breaks, the relay will not move; With optical coupling isolation, triggering more reliable, more stable. EASY to INSTALL: Equipped with screwed terminal plate and fixed bolt holes(diameter: 3.1 mm) on both sides for easy installation. High/Low level trigger can be by jumper. Very versatile, you can reverse the input logic with the jumper. Input Interface: DC+:connect to power positive (according to the relay voltage range) DC-: connect to power negative IN: relay module trigger pin (high or low level trigger Optional) Relay Output: Normally Opened (NO): normally open pin of relay. NO pin is not connect to COM pin when relay off.NO pin is connect to COM pin when relay on; Common pin (COM): Common pin of the relay; Normally closed (NC): normally close pin of relay.NC pin is connect to COM pin when relay off.NC pin is not connect to COM pin when relay on. Material:ABS colour:Photo Color Package Contents: 2 * Relay Module Only the above package content, other products are not included. Note: Light 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.