【Safe and Effective】The N11 bark control device emits ultrasonic waves of 25 KHz, which are inaudible to humans but it effectively interrupts dogs concentration without causing harm, and their response is to stop what they were doing. It is effective in stopping unwanted barking or preventing dogs from eating unsafe food. Ultrasonic sound is a humane way to stop bad behavior in dogs. 【30ft Effective Range】N11 Anti-Barker is equipped with a 25KHz ultrasonic head to help you quickly, effectively and painlessly change every annoying, disruptive and unsafe behavior. Recommended for indoor and outdoor 30 ft unobstructed range. Simply press the button and point the device at your dog, the sonic bark deterrent will not shock, vibrate, touch your dog's skin or affect your dog's hearing, so it is harmless to your dog. 【365 nm UV】The N11 Anti-Barker is paired with a 365 nm UV wavelength to fulfill some animal fluorescence detection needs. For example, animal part of skin disease detection/fungus detection/cat moss detection/urine detection etc.It is recommended that you turn on a violet light in a dark environment to check.