SWISSINNO Battery Ultrasonic Rodent Repeller – Portable Mouse and Rat Deterrent – High-Frequency Ultrasound – 20m² Coverage – 8 x AA Battery Operation – 6–7 Weeks RuntimeAdvanced Ultrasonic Technology Produces powerful high frequency sound waves specifically tuned to disturb and drive away mice, rats and similar rodents, creating an environment they avoid while leaving the area undisturbed for people. Cordless, Battery Powered Operation Runs for 67 weeks on 8 x AA batteries (not included), giving you complete flexibility to place the unit in areas without mains electricity such as lofts, cellars, garages, sheds,