Stop your dog from barking excessively when you use this Fist Alert Bark Genie device. This handheld unit uses four AAA rechargeable batteries for power. It can be mounted on the wall or used in your hand when on the go. It is weatherproof and has an ergonomic design that is ideal for carrying while walking your dog. The device uses a safe ultrasonic sound that only dogs can hear. It works on all dog breeds from up to 15 feet away.