Suitable for All Types of Dogs - Ultrasonic dog barking control has 3 adjustable sensitivity and frequency levels (Ultrasonic dog bark control has 3 adjustable sensitivity and frequency levels (low(15ft), medium(30ft) and high(50ft)) to help you choosedifferent waves and handle different waves easily barking. Adjust the training frequency every week to maintain the training effect. Safe for Dogs and People - The anti barking device is safe and effective for dogs of all types and sizes (5-120 lbs). For dogs 6 months to 8 years old. Please turn the knob to test different frequency bands for best results. If the dog is hard of hearingor aggressive, the device may not work as intended. Upgraded Dog Training & Behavior Aid Tool - Anti barking device adopting the latest ultrasonic technology, the anti barking control will automatically emit high-pitched tones that only dogs can hear. Automatically sense the dog's sound, once thedog stops barking, the ultrasonic barking controller will automatically stop emitting ultrasonic waves. 50ft Effective Range - Outdoor barking control is automatically activated when barking is detected up to 50ft away. Can be hung on trees, indoors, outdoors walls or fence posts to deter dogs from barking. Weatherproof and Durable - Our anti bark device is waterproof and durable enough to withstand any weather conditions; making it a great anti bark device for controlling your dog. Runs for up to 1 month on a 9-volt battery (not included) depending onuse.