Annie got used to the vibrating collar, in less than a month. I was so disappointed. She didn't react at all, even when it began vibrating, even when I selected the highest setting, so I began investigating other methods to stop her hysterical, non stop barking. I contacted a "no bark" training behaviorist. After discussing Annie's barking on the phone with the behaviorist, I learned that her fee would be $1800 for a one time, 3 hour, home visit, and I could call her via telephone if Annie reverted to non stop barking when visitors entered my home. I thought this amount of money was way beyond my budget, and there was no guarantee that it would stop the barking, so I declined the behaviorist's services. About four months ago, I heard about a training device that produced an ultrasonic sound, beyond the range of human hearing, and as I found one on Amazon, for less than $20.00. I thought this was to good to be true, but purchased one anyway. The first few times I used it, the barking stopped immediately. Annie looked so surprised. It has now been about four months since I got the device, and now, all I have to do is show her the device, without even turning it on and she is quiet immediately. I am so pleased with my purchase, and can now have a pleasant visit whenever some on comes to the door and into my home.