High Efficiency Ultrasonic Mouse/rat Repeller Recently, we noticed some customers complaint mice/rats are more active in the first 2 weeks of using the machine, It is because the ultrasound with multiple frequency wave stimulates the nerve system of rodent animal, they feel uncomfortable, and are looking for a route to escape. Please keep on plugging in the repeller, it will work well and expel mice/rat from your place. Professional manufacturer specialized in expelling mice and rats, and other pest control equipment. Top seller in rodent control devices.Automaticly change ultra-sound wave frequency between 25-45Khz in order to avoid mice/rats to generate adaptivity to single wave ultrasound. Chemical/toxics free. Inaudiable ultrasound from this device is friendly to Human, dogs, cats and other non-rodent pets. Plug in and no maintainance needed for whole working life. Commercial grade ultrasound generator makes an invisible shell to protect your space from mice and rats bothering. Wide usage in all rooms and space of your home, office, restaurant, store, library, garage and work-shop. keep at least 6 feet from wet/humid places, such as bath room tube, water taps. etc. Please let the device to continuously work for 3 to 4 weeks to reach best performance. Once buyer post review on Amazon.com, please send you order number and date of purchase, 5% will refund as discount.