Description Adjustable Frequency Lasting Eeffective - Compared with similar products, the bark control device has extra frequency conversion adjustment function, which can slow down the dogs resistance to the fixed ultrasonic frequency, prolong the effective time of our ultrasonic dog barking control devices, and make the training effect more obvious. Safe Harmless - The ultrasonic frequency above 25hz can attract the dogs attention very well. When the dog barks and makes trouble, using the anti-bark device can interrupt the dogs behavior.Plus, the ultrasound will not affect the health of the dog. Its effective for dogs of all types and sizes of age 6 months to 8 year-old. Simple and Easy to Carry - One-click operation of the barking control devices can release ultrasonic waves to attract the dogs attention and interrupt its bad behavior. Press and hold the button until the green light goes out to turn off the anti-barking device. The product is small in size and comes with an electrostatic wristband, which can be carried around. Healthy Dog Training Tools - In addition to preventing the bad behavior of dogs, the barking control devices can also be used as a good dog training tool. All you need to do is stop your dog with a anti barking device when he does something bad, and once he responds positively, reward him to strengthen his memory. After consistent training, it will become a smart and friendly dog. Multifunction - The anti barking device has strong anti-interference ability, and the accurate effective range is 16.4 feet,and can be used effectively no matter indoors or outdoors. While preventing your own dog from barking, it also prevents being chased by unfamiliar dogs when you go out for a run.