How it works - cat repellent emits ultrasound, ultrasound of different frequencies stimulates the central nervous system of the animal. This will make the animal uncomfortable and immediately flee the area. It is not toxic to human body. Occasion for Use - Suitable for any places where they are damaged and disturbed by animals, such as farms, yards, gardens and orchards, etc. Note - The eviction of animals will not take effect immediately, and it may take 10-15 days to exert their full deterrent effect. It is recommended to change the frequency regularly. Most animals have a wide range of hearing, but only one is the most effective frequency. If the recommended settings do not work, please set different frequencies to meet your specific needs. FREQUENCY CONTROL BUTTON: 0: close 1: 13.5 kHz-19.5 kHz. Repelling mice, rats, dogs, foxes, minks and other animals. 2: 19.5kHz-24.5kHz. Including cats, raccoons, skunks and other animals. 3: 24.5kHz-45.5kHz. Expel bats, birds, rodents and other