I purchased one of these collars, because I liked the description. It has two tripping mechanisms. It is voice activated and vibration. It needs both in order to correct. Also, The way that I read it has 18 levels of stimulation and it automatically works through all of them each time the dog barks...WRONG
It has three levels with 6 sub levels each and it starts at lowest, working its way up. The problem is that it resets to the lowest if the dog does not bark within 30 seconds (maybe a little longer).
Finally, I tried it out on a dog and it worked for a day. the next day he was barking up a storm. I have yet to have it keep a dog from barking. I am much happier with the Tritronics collars. I tried the test light to see if it works and the light flashed up a storm. I did the idiot test and put it around my neck, while talking (shouting really). It did not work for about 8-10 times then it got me. If a dog does not get hit each time, I don't see how it can learn not to bark.
I would avoid this product like the plague.