This tool has been extremely helpful in mapping the wiring in my new home. It is the size and shape of a pen, and could not be simpler to use: Touch the plastic tip to a cable, switch, receptacle, or fixture where an AC potential in the range of 90 to 1000 volts is present, and the LED lights up.
It is “non-contact” in the sense that no electrical contact is made between the tester and the circuit, which is faster and safer than a traditional two-lead multimeter or circuit tester.
The tool includes a battery test button to verify that it is working in the negative test case, which is an essential safety feature if you’re actually going to fiddle with the wires. This model features an “always on” design, which is both more convenient, because you don’t have to fiddle with a power switch, and (arguably) safer because it eliminates the possibility of false negatives due to absentmindedly forgetting to turn it on (or accidentally turning it off) before taking a reading.
Advertising boasts of “special low power circuitry to sustain battery life.” I have only owned mine for a couple of weeks, so I can’t vouch for the battery life, but I note that it came packaged with two energizer AAA cells already installed, implying that Fluke is confident of battery performance over the unknown months or years the packaged tool might sit on a shelf or in a warehouse before purchase by the end user. The batteries are replaced by unscrewing the barrel at the tip.
The Fluke 2AC has performed flawlessly for me. The only “con” I can identify is the price. There are several of these non-contact voltage testers on the market, and comparing their prices among Prime-eligible Amazon items indicates that, as of this writing, the 2AC is on the high end of the distribution at $24.95, with the low-end tester coming it at $7.99. Personally, I don’t mind paying that premium for the Fluke name, but I imagine if you’re working carefully and paying attention (as you should be anytime you’re messing with building wiring) a less expensive model will probably serve your purpose just as well.