I did not expect the quality of these cabinet alarms. NICE JOB!!!

I attach 18 guage lamp cord and insulated alligator clips or lightbulb socket or wall plug. I can hear them when down at pannel

Pro: I like the audible. I bought it for locating plugs and lighting circuits via breakers. Con: you need to move fast after plugging it in because it heats up and stops beeping and flashing. It’s okay on a first floor but a second and third can be a real pain rushing to breakers before it shuts off due to overheating.

Seems like this is only designed to use fork terminals; I'd prefer ring terminals.Otherwise, it's well-made and quite loud.

I have 2 instances of this model become hot and produce burn smell when connected directly to 120v outlet for 3 to 10 minutes. Perhaps they expect some sort of current limiting resistors???

Features that are combined in a single Device makes electrical signaling easy to visual & audible tone can,t miss a condition That needs a immediate response .

The first 2 of 5 units lose buzzer volume the first 10 minutes & got hot with enough ventilation. Wished it stay at 85 db. Sounds like a truck backup beeps.

Before drilling holes and mounting these, I wanted to test them to make sure they worked and would meet my needs. At first, I thought all five in the pack were bad when none of them worked, but that turned out to be a bad jumper wire. However, before discovering that I had a bad jumper wire, I completely disassembled one to figure out what was wrong with them and how they were constructed, which I will include in this review.First, let me give a general review before I jump into the technical details of what's inside them. Overall, they will work OK for what they were designed to do. They do, however, waste power when running, dissipating approximately 2.8W in heat alone to drop the 110/120VAC power to a level low enough to run a couple LEDs and a buzzer. As such, make sure you keep them well ventilated and don't block the slots on the side, as it gets a little toasty if it runs for long.The flashing LEDs are sufficiently bright to get your attention, provided the room isn't too bright. However, the buzzer isn't nearly as loud as I had hoped for and would have liked it to have been two or three times as loud as it is, if not more.As some of the other reviewers noted, the connection terminals are a bit flimsy, so don't over tighten the connections, but they should otherwise make good contact and are separated by enough plastic material to keep them insulated so they don't short.Now for a more technical analysis ... the first observation as I opened one up was the horrible soldering job. Everything made good contact with no cold solder joints, but there was lots of random solder blobs stuck to random places on the board. I even found a rather large blob of solder in the bag they came in that had fallen out of one of them. The blobs are probably not enough to short something and cause issues, but it was the first observation as to the quality and its assembly.For power regulation, this thing uses a couple of large resistors in series as a voltage divider. One was a 3.5K and the other 5.6K, with the LED/buzzer circuit in series between them. These appeared to be 2W resistors, which are barely large enough, as they are dissipating (per calculations) approximately 2.8W combined.The input power, after feeding through those resistors, goes through a full-wave rectifier bridge composed of two A7 (BAV99) dual diode packs. The output of the full-wave rectifier goes to a 330uF/10V capacitor. That becomes the main "unregulated" power that feeds the LEDs and buzzer. That unregulated power then goes through a 2K resistor to a zener diode (which wasn't labeled and I didn't bother measuring its voltage, but is probably around 5V) to create a "regulated" voltage.The LED and buzzer part of the circuit consists of two strings of 3 parallel LEDs (2 surface mount and 1 through hole) of which only 1 LED is populated in each string with the buzzer in between the two strings. In other words, it's LED, buzzer, LED with four vacant LED footprints that aren't populated. My guess as to why the parallel LEDs aren't populated is that due to the nature of LEDs, if the LEDs in parallel aren't absolutely exact on their forward voltage drop, one will inherently be brighter than the other(s) and one (or more) may possibly not even light. More than likely, it didn't work well to have more than one LED in each string so they left the other places vacant. But that's just a guess. In any case, the assembly consisted of two red LEDs and a buzzer in series.Powered from the regulated voltage of the zener diode, there was a circuit chip (in a SOIC-8 package) that had its top markings removed. At first, I thought perhaps a 555 timer, but then realized that no, that would require more parts than were present and the pinout didn't match. Instead, the pinout appears to be consistent with a Microchip PIC, 12F5xx/12F6xx family device, with V+ on pin 1 and GND on pin 8. The output to control the LEDs and buzzer was on pin 7, and a solder selection jumper on pin 5 to ground (which wasn't jumpered). The output pin 7 went through a 2K resistor to a J3Y (S8050) NPN Transistor which turned on/off the LEDs and buzzer. Jumpering the jumper on pin 5 made no discernible difference to the LED/buzzer operation, so I have no idea what that jumper is for -- perhaps it's a timed shutoff or something and I just didn't let it run long enough to test? Who knows.That's pretty much it for the circuit. Due to the lack of real voltage regulation, when the buzzer sounds, the volume noticeably drops as the voltage begins to drop and makes more of a "chirp" sound. I think that's part of what makes the buzzer not as loud as it could/should be.A much better circuit would use a switching buck regulator to make a consistent voltage supply without wasting power in heat loss through a couple of resistors and would make the buzzer louder and not changing in volume as much as it does during each "chirp". But, such a circuit would be much more expensive than what is there and I'm sure it is why it doesn't use such a voltage regulator.All in all, they are OK. Nothing too exciting. They will get the job done, as long as you don't mind it wasting electricity and can dissipate the extra heat it generates.