[UPGRADED DOG TRAINING AND BEHAVIOR AID TOOL]: Utilizing advanced ultra technology, this anti-barking device automatically emits a high-pitched tone that only dogs can hear. It detects barking and emits ultra waves to help deter the behavior. Once the dog stops barking, the device automatically stops emitting sound. [ANTI-BARKING FOR ALL SIZES AND BREEDS]: This device features 4 sensitivity levels to suit different environments and dog sizes. Adjust the sensitivity level based on your surroundings—Level 1 is the least sensitive and Level 4 is the most sensitive—to achieve optimal performance. [SAFE FOR DOGS AND HUMANS]: This barking control device uses no electric shock, no unpleasant odors, and no loud beeping. It is designed to be safe for pets and harmless to humans. The ultra waves help discourage barking, making it ideal for maintaining a quiet environment at home. Note: Effectiveness may vary for dogs with hearing impairments or aggressive tendencies. [USB RECHARGEABLE DOG BARKING CONTROL DEVICE]: Equipped with a USB charging port and indicator light, this device is convenient and easy to use. A 5-hour charge provides up to 30 days of operation, eliminating the need for frequent battery replacements. Ready to use right out of the box. (Recommended to fully charge before first use for best results.) [STOP DOG BARKING INDOORS & OUTDOORS]: Tested for optimal performance within a range of up to 32 feet, this device offers a hands-free alternative to traditional training methods. Simply turn the knob to activate and begin training your dog’s behavior. Suitable for use in various settings to help reduce barking from dogs nearby.