PetSafe Ultrasonic Bark Control Collar Uses ultrasonic sound to eliminate or reduce excessive barking Microphone detects your dog's barking to ensure another dog barking or other noises will not cause a false correction Water resistant collar is suitable for light rain or wet grass exposure Replaceable 3-volt lithium batteries (included); Includes low battery indicator No Bark Guarantee: Some dogs may not be responsive to ultrasonic correction. If this product is not meeting your needs, please contact PetSafe Brand. Call, chat or email the PetSafe US-based customer care specialists six days a week