ITEM NAME:8-way Relay Module 12V with Optocoupler Isolation Supports High Low Trigger GBL Descriptio n Specification:.Product list :1pcs 8-way Relay Module 12V With Optocoupler Isolation. 8-way Relay Module 12V With Optocoupler Isolation. NC1--NC8: relay normally closed interface, which is short connected with COM before the relay is sucked in, and suspended after the relay is sucked in;.