The PetSafe Ultrasonic Bark Control effectively deters barking when it is worn. When the microphone picks up the sound of your dog’s bark, the unit emits an ultrasonic tone that can be heard by your dog, but is silent to most humans. Startled by the high-pitched tone, the dog should stop barking, as it will associate its bark with this unpleasant noise. Automatic Safety Shut-Off Microphone detects bark Uses 2 x 3 Volt lithium batteries (included) Battery usually lasts 1-3 months Fits neck sizes up to 68.6 cm Water resistant
