PetSafe Bark Control - Ultrasonic Indoor Bark Control - GraySay goodbye to excessive barking with PetSafe Bark Control! This compact device emits a 2 second ultrasonic tone whenever your dog barks, teaching them to associate barking with an unpleasant sound. With a range of 25 feet, it's perfect for indoor use. Train your dog to be a good neighbor with this easy solution! Features: Range up to 25 feet Uses 9v alkaline battery (not included) For indoor use only water resistant Uses high frequency ultrasonic