As the name suggests, this repeller is for larger houses and covers a truly impressive 4000 square feet. Like the repeller for the Whole House it also uses both ultrasonic and electromagnetic waves, but also has many additional features. This unit is equipped with three pest repelling functions, including four powerful ultrasound settings allow you to target the pest you don’t want: 1. Mice, rats or squirrels 2. Spiders 3. Crawling insects 4. Mosquitoes Ultrasonic waves cause auditory stress to mice, rats, squirrels, ants and most crawling insects, which disrupts their normal behaviour patterns and makes it uncomfortable for them to stay in the room where the unit is positioned. Ultrasound does not penetrate walls or other solid objects, and is best positioned with an unobstructed ‘view’ of the target area. Pest-Stop Professional uses two ultrasound speakers for added power. Random or continuous electromagnetic settings drive pests out from their nesting places in wall and ceiling spaces throughout the building. The electromagnetic function uses every electrical cable in the building to carry and transmit a signal, which can be detected by the pests up to 1 metre from any cable, even inside wall and ceiling spaces. The mosquito setting emits an ultrasonic signal, which deters mosquitoes in the room where the unit is positioned. Direct plug-in design – use almost anywhere. Safe and effective – no chemicals or traps. Will not affect humans, cats, dogs, fish or birds. DIY Industry Awards 2002 – Winner of Best New Hardware Product category!