Review on KAIWEETS Voltage Tester: Non-Contact And Contact Pen For 12V-300V NCV Testing, LCD Display, Live/Null Wire Detection, Buzzer Alarm, And Wire Breakpoint Finder - VT500 by Joseph Neal

I got this voltage tester just to use as a quick and easy tool to check whether a wire is live, without needing to contact the metal or deal with multiple probe connectors like a digital multimeter has. I have a non-working ceiling fan to replace and this seems well worth the money for the added safety check before I start touching the wires. It works perfectly for that with AC-powered wires. When I put the probe against any insulated wire in my house plugged into an outlet, the device beeps. It remains silent when against unplugged wires. Though now I've learned some ceiling fans are DC too, so it doesn't eliminate the risk for my project. I wouldn't use the tester for anything but checking live wires contactlessly probably. The instructions warns that "users should be extremely careful when testing voltage>30v, since such voltage may cause the risk of electric shock", and that works as a general warning (US home outlets are generally 120v and 240v), but I do wonder how safe the device actually is if you are using it in contact mode. It has modes to check continuity of a wire and polarity of a battery, but those modes require you to make a circuit with one hand on the CONNECT button and the other hand on the opposite end of the wire/battery, meaning that that you aren't really insulated from the device. So I'll avoid using it to test the AC voltage in contact mode. I'm also not clear how accurate the AC voltage reading can be with a single probe. I don't really have a need to check continuity of wires and polarity of batteries either. But it is perfect for checking whether an AC wire is live. It even comes with a built in LED flashlight so you can see the wires in the dark.