This product works exactly as described. Because of my job I wanted to make sure I could rely on this device working ALL of the time. I kept notes and used it on 21 dogs in a 30 day period. All breeds and sizes.
19 of the dogs instantly stopped barking and walked away a few feet. Two of the dogs did not. I believe it is because they were deaf. This product seems to be most successful when used within 10 feet of a dog.

It's a little unclear, looking at the device, which setting is for what. However, I found that the third setting on the right is the one that works to keep dogs away and to make them stop barking. The middle setting doesn't seem to do anything but I'm probably not understanding what it is for.

I have used the device for 3 1/2 months and have not needed to change the 9volt battery.

I am a delivery driver and after being attacked several times I'm horrified when I pulling up to a house with dogs. This product has completely changed my day-to-day work life.

As others have mentioned, instructions are in engrish. Labels molded into the yellow plastic next to the mode switch are all but impossible to see. There are three positions: first position (full forward) is flashlight only, second position is for sound plus flashing light, third position is for sound only. Not sure if there is a difference between the sound frequency and volume level in the second vs third position since it is not audible to humans. The button on the opposite side of the device triggers the sound (assuming the switch is in position two or three).

So far this device is working for us: really gets the dog's attention when she's doing something wrong. In my case, this is when my dog starts growling or otherwise acting aggressive during a walk when we approach other dogs. Momentary press of the button (in my coat pocket) and the dog immediately stops growling and looks around at me. Only took a couple of times before the dog started associating the annoyance with her behavior and seems less apt to even start up.

I have noticed that the device does not always get the other dog's attention though. My thinking is that perhaps dogs, like people, start to loose their high frequency hearing as they get older: so perhaps the sound just does not register with some dogs based on age or perhaps just the quality of their hearing. This *might* also explain some of the negative reviews.

No idea about the durability of the device as we've only had it a week.

Quality is a little less than I expected, but it works and for 10.00 it is worth it.

I got this instead of the Dazer-type electronic deterrent since it cost nearly half as much, and it's smaller. I had an incident where stray dogs got into our yard and one push of the button made them instantly turn around and leave. It also works against cats. It makes an inaudible (to most humans) noise and flashing lights on the front which also function as a flashlight without the sound. It has a milder setting for training your animal which would work the same way you might use a dog whistle. So the unit itself works great. My one complaint is that the instruction manual (which I think was originally written in German or Dutch?) is complete gibberish for the English section. I would have been happy as a native English speaker to accept US$2 to give it a once-over and write something professional-looking.

I have two smaller dogs around 14 years old that constantly growl at each other. This distracts one of them and breaks up the fight. The other dog? She is either going deaf or has very selective hearing. She was always stubborn, so I can't say for certain if she hears it or not. It definitely works to get the first dog's attention, so it is useful. It feels cheap, but it wasn't all that expensive.