Well, because it may work on some dogs, but it didn't do squat with Ruger. I even called the company several times to get advice and we wound up returning it. 
 
Tonight Ruger went downstairs and started crazy barking out the window. "Quiet," didn't work - never does, so I put the collar on him.  He barked a couple more times, made a sound like "Hey, WTF," - and hasn't made another sound all night.  I just took it off and he's still quiet. 
I will admit I feel better since I put the resistor on the collar, and now it's more like getting his attention.  I want to thank everyone for convincing me to rethink the bark collar. 
The way I see it if you are going to train your dog you have to catch him the instant he does something wrong. As we all know, you don't rub your dog's nose in a mess he made, especially when you didn't see it happen. If you catch the dog in the act you are supposed to startle him and place him where he's supposed to go.  The collar startles the dog the instant he barks. Often, all I have to do is put the collar on him and he stops and won't bark again. 
Some of you obviously swear by vibrating collars, ultrasonic devices and sprays, but none of these devices worked at all on my or my girlfriend's dog.  This is also born out in the ratings these devices get. 
Again, I would never hurt my dog, and many of you make it sound like I've got Ruger strapped to a little electric chair. 
