Pen Tester Chaldean Non Contact Voltage Detector AC Tester Pen, Safe and Efficient

You really should have a voltage detector if you ever do any electrical work. It makes the occasional wiring job 10X quicker... You don't have to fumble with multimeter probes, and can check for power on insulated and capped wires easily. If you're working on a 3-way switch, ceiling fan wiring, or any outlet that has more than one set of wires, this makes it far quicker to track which are live coming-in, which comes on when you hit the switch, and which need to be supplied power out of the existing outlet. Immensely useful when replacing standard outlets with GFCI outlets. No need for a circuit breaker detector/tracker when you've got one of these.This one is not quite as sensitive as name-brand voltage testers. It wont alert if you aren't right over the hot wire... Not close-by, not touching the other side of the extension cord, you have to be right on it. However, it's less sensitive to false alerts from bumps and shocks than my old one, which is a plus.Worse, it's missing an ON/OFF switch. It doesn't entirely need one. It actually shouldn't draw any power just sitting around, but movement of a tool belt/box or being inside a vehicle will just occasionally cause it to beep/flash and draw a little power. That's to say nothing of the flashlight button that could accidentally get bumped or held down. It only draws 20mA when beeping, and the flashlight LED is only 1mA, so it'll take quite some time to drain a pair of AAAs even in the worst case, but if this is unused but moving around for months, the batteries will eventually go flat. You can opt to turn just ONE of the two batteries backwards to safely disconnect it, but I'm concerned repeatedly opening/closing the unit will eventually cause the plastic latch to fail. If you use it frequently, might as well just tolerate the extra power drain.Still, I expected those issues going in, and I ordered it anyhow. At just $4 I still say it deserves 4-stars. It's $10-15 less than any slightly-better, name-brand units I saw available, so I'll take the trade-offs for the price. If you go looking through other voltage detectors, just be careful you don't get one that takes special "watch batteries"... Replacing those can cost more than the detector itself, while a pack of 8xAAA batteries goes for $1 at the nearest dollar tree store. Also, cheaper units often lack a buzzer/beeper and only have a flashing light to indicate voltage.I read lots of reviews with horror stories about receiving defective units, but no problems here, mine works great. It did take 3-weeks to arrive, though, and would be double that if you happen to get a defective one the first time and have to wait for replacement... Mine was sold by: ChinaTrade. Batteries NOT included.Currently cheapest listings I've found for this item:*  LED Light Ac Electric Volt Voltage Tester Volt Alert Pen Detector Digital Novedades 2015 Electricas Ac Voltage Detector *  TOOGOO(R) AC Non-Contact Electric Voltage Alert Detector Tester Test Pen 90~1000V LCD *  90-1000V LED Light AC Electric Voltage Tester Volt Alert Pen Detector Sensor *  AC Voltage Tester Pen 90~1000V Non-Contact Volt Alert Sensor Detector Stick