1.Electromagnetic waves 2.Anion 3.Ultrasonic 4.Electromagnetic waves + Anion+ Ultrasonic+nightlight 4 in 1 Multifunctional Pest Repeller Electromagnetic waves +Anion+ Ultrasonic ... various of pests, but also can make it as a air purifier, it will control roaches, ants, spiders, mice, ... a stream of beneficial anions to disinfecting, clean the air, bring you a health life.5.Triple superstrong function ...