Review on SainSmart 101 70 102 8 Channel Relay Module by Nancy Gray

This 8 channel relay board works as expected. Please note that you need a separate 5VDC power supply to use the isolators. This was certainly necessary in my application. Otherwise, back EMF and/or noise would return to the Arduino and cause failure. It is important to note that the ports on the bottom are open. If you're using AC power, you'll need to insulate them. In my case, the case it fell into does this. If not, open AC power is seriously dangerous. Still, I would isolate.