The Ultrasonic Dog Bark Trainer is a harmless and effective solution for calming barking dogs. Our bark control devices are designed to emit an inaudible sound ranging from 35 to 45hkz that only dogs can hear, using two transmitters up to 50 feet away to deter hostile dogs. Lightweight and portable, it won’t harm the hearing of pets or others pets, making daily training safer. This anti-bark device can be used for jogging or walking, cycling, park, car, beach, etc. . With a built-in bright LED flashlight, it’s perfect for nighttime rides or low-light situations. This is a versatile trainer that can be used as a flashlight, as well as for dog training and dog repelling.