[Two-in-One Frequency Modulation Technology]: The dog trainer emits ultrasonic waves of different frequencies. After a long period of familiarization, this may prevent the dog from developing immunity to a certain frequency of ultrasound, becoming desensitized and ready to use others. sound waves. [*You and your dog]: The ultrasonic bell protector adopts the latest ultrasonic technology with 22-25KHZ frequency. The sound does not affect humans, but it can easily attract the dog's attention and prevent it from misbehaving. When your dog is pranking you within 5 feet, just hold down the button and point it at the dog. [Effective Dog Controller]: The ultrasonic bell controller is suitable for dogs from all sizes (except dogs under 6 months and aggressive dogs), which can help owners control unwanted barking and prevent excessive pointing. Behaviors provide safe and effective solutions for barking, digging. , hunting, eating dirty or fighting etc. USB CHARGING PORTABLE SIZE: Unlike other bark control devices that use AAA batteries, Foonii's ultrasonic bark control device has a built-in 300mA rechargeable lithium-ion battery. A full charge takes 2 hours and lasts up to 20 days. , The compact ringer is perfect for portable devices. When the device is in a low power state, the red LED will flash. [SUITABLE FOR INDOOR AND OUTDOOR ACTIVITIES]: The dog bark repellent can be used indoors to prevent unwanted barking and train your puppy at home.