Review on SMAKN® 4 Channel Module Triger Self Lock by Fred Vazquez

Okay, that's really good. I've tried a few different 4 channel relays and some of them don't even work. It works and has some nice features. First, you can set it to trigger on the ground input or on the positive input. Second, it can be configured as a latching device (meaning that a momentary input will trigger the relay and the relay will remain on). Then another momentary pulse switches the relay off. Third, you can set it up so that only one relay is on at a time. So if you activate an input that relay will be energized, but if you activate another input the first relay will be energized and the current relay will be energized. Of course you can also set it up so that the relay fires only when the trigger is activated. Remove the input to the trigger and the relay will work. A very nice little device. It even has trigger review buttons.