wow! i have had a barking problem with my rescue dog since we got him 2 years ago. i had tried everything, my neighbours had made a point of letting me know that it was a problem. so i decided to give this product a go, even though i knew it wouldnt work. well how wrong i was, this has changed my life, i can now go out for more than an hour, and i no longer have to use dog sitters when i'm out for longer. it is amazing, i now come home to peace and quiet, and i have been told that it is quiet while i am out. what a wonderful product, i didnt think anything would work, but this has. i would recommend this product 100%.