Cats can detect frequency from 55Hz up to 79kHz.
Some cats are more susceptible to the Ultrasonic Sound then others. Based on the breed, age, size, and just the general nature of the cat.
Can Ultrasonic Sound harm cats or other pets?
The sound will not harm them but deter them.
How long do ultrasonic pest repellers last?
This is an electronic device that does not have an expiration time, just like any other electrical appliance. Pestrol offers 12 months warranty.