The anti bark device is designed with speakers and 4 adjustable modes. Level 1 - variable frequency (15-30KHz). Level 2 - 20KHz frequency. Level 3 - 30KHz frequency. OFF level - stop switch. This dog trainer can effectively stop the dog from barking up to 33 feet away. Built-in 1500mAh lithium battery, the dog bark stopper can stand by for 30 days after 5 hours fully charged. With IPX4 waterproof and hanging rope design, the anti bark device can be placed or hung anywhere indoors and outdoors. The anti bark device ultrasonic dog barking uses high-pitched ultrasonic technology is harmless to pets which is higher than human hearing range, but it will attract dog's attention without painful stimulation. The ultrasonic dog bark control device works on most breeds and sizes, but does not work on deaf or hard of hearing dogs. Suitable for large/medium/small dogs. Some dogs may be afraid or dislike the sound of ultrasound, not stop barking at first. Please allow up to 2 weeks for training. Number of parts delivered: 1 Color: Black Size: 85*110*48.5mm