This 4 Road/Channel Relay Module (with light coupling) 12V module meet the safety standard as control areas and load area have the isolation groove. Optical coupling isolation module.
The triggering of 4 Road/Channel Relay Module is reliable, more stable. The double FR–4 circuit board design, high-end SMT process. It has power and relay operation instructions. Relays terminals (C, NC, NO) are accessible through screw terminals which makes wiring up the board very easy.