Review on Klein Tools RT210 Outlet Tester: Detect Common Wiring Problems in GFCI / Standard North American AC Outlets by Steve Hauck

I made this to find out why all my APC backup batteries and splitters keep showing a site wiring fault. Of course as I live in an apartment I asked the maintenance crew to take a look and they said there was no problem. Enter this device. I checked all my outlets and they all showed open ground. I turned off the power, unplugged the outlets, and connected all the ground wires. I asked our repair team to check the outlets again. After showing them that there was open ground, it was discovered that none of the ground wires were actually connected through the outlet box. This little device saved me from a possible fire or short circuit/electric shock. For $9, it's a really handy tool, even if it's just for testing your outlets to make sure they're working.