How the ET Pest Control repels bats: The ET Pest Control is an electronic plug in pest repeller that uses both ultrasonic and electromagnetic sound frequencies causing a chaotic unstable environment for the bats. The electromagnetic high impact repelling technology is designed to repel deep within the walls of your home or work environment. This repelling technique helps greatly as bats have been known to hide in walls, attics, and other unseen able places. The ultrasonic variable sound frequencies are in constant changing frequencies so that the bats will not become tolerable to one signal. The sound frequencies will interrupt the bats' communication skills, eating habits, and flight pattern forcing them to leave the area. It takes time to repel bats. It can take up to 4-6 weeks depending on how severe/non-severe your bat problem is. Please see our Proper Application page for the coverage area you may need to repel the bats. All you do is simply plug in the ET Pest Control into any household or business outlet. Also, for the hard to reach places, you can use an extension chord and plug in the pest repeller facing toward the infested area. Both the extension chord and the pest repeller will repel the bats at the same time.