Do these work? I've heard of dogs competing with the tones, or barking just to hear it, but what about the ultrasonic ones? I am assuming the other ones, make a tone that human ears can hear, the ultrasonic ones you can't like a dog whistle. Just thought maybe it would help curb Cookie's barking, but they're fairly expensive and I don't want to buy it if it doesn't work. Has anyone else used one of these before?
Thanks for any info anyone can give me!



