A snake-repellent device emits a high-frequency sound that is unpleasant to snakes, causing them to avoid the area around the device. The sound emitted by the device is usually in the ultrasonic range, which is above the range of human hearing. This means that the sound is not audible to humans, but it is very effective at repelling snakes.

When a snake comes into the range of the device, it is hit with a blast of high-frequency sound. The sound is so unpleasant to the snake that it immediately turns and slithers away, seeking a quieter and more peaceful location. This behavior is known as avoidance behavior and is the basis of how the device works.