This 4 Channel 12V Relay Module with Optocoupler meet the safety standard as control areas and load area have the isolation groove. Optical coupling isolation module.
 
The inputs of 4 Channel 12V Relay Module are isolated to protect any delicate control circuitry.
 
A wide range of microcontrollers such as Arduino, AVR, PIC, ARM and so on can control it.
 
The use of such high-voltage relay eliminates the risk of heating up of the relay as electromechanical relay limit the current consumption in accordance with a voltage rating.