PNT2200 Plus ULTRASONIC SILENT  with LED PNT 1100+ ULTRASONIC ULTIMATE REPELLER combines our 2 unique technologies, “Automatic Frequency Change” and “Adjustable Sweeping Speed” which can prevent rodents from getting used to a single-frequency sound by changing frequency and speed all the time. These intense ultrasonic waves directly attack rodents’ auditory and central nerve systems to drive away these unwanted animals from your place without using toxic chemicals or killing them.