describe Features: Pet-Friendly Anti-Bark Device: This ultrasonic anti-bark device emits a steady frequency tone that only dogs can hear, prevents dogs from barking and calms them down. No irritating smell, no electric shock, dog anti-barking function that only works when the dog barks. Great for creating a quiet ward for dog lovers and deterring bad behavior. Effective for dogs of all sizes: Ultrasonic bark deterrent has 3 adjustable sensitivities and frequency levels (15-30 kHz for large naughty dogs; 20 kHz for training dogs; 30kHz for small dogs) to prevent different Small and large dogs bark easily. Adjusting the frequency every week can maintain the training effect. EASY TO USE: This rechargeable bark controller with LED display is effortless to use. When working on 3 different levels, the light will flash blue every 6 seconds; when the sound barking is triggered, the red light will stay on for 3 seconds; when the battery is low, the red light will flash. OUTDOOR AND INDOOR USE: The human bark unit with IPX4 rain resistance and portable hook can be easily hung on a tree, wall or fence post. But when it rains heavily, it is best to take it back to prolong its life. The ultrasonic dog device can be placed on desks, walls, and shelves with a height of more than 1.5m, and can more effectively regulate dog barking, digging, fighting, etc. Material: ABS Package contains: 1 * Anti-bark device control 1 * Mounting screws and holders 1 * USB charging cable 1 * User Manual