The Victor mini Pro pest chaser emits high frequency, variable sound waves that Effectively repel rats and mice from your home. The sound is completely inaudible to people and non-rodent pets. Since you can't hear it, a red led light tells you the unit is working properly. You just need to plug it in and forget about it. Varying intensity and frequencies of ultrasonic sound waves prevents rodents from getting used to the Victor mini Pro pest chaser. Reduction in rodent activity should occur within 6-10 days. There are no dead rodents to dispose of so it minimises human contact with mice, rats and other disease-bearing rodents. This M752P-UK will cover an average-sized room and is suitable for any inside space: kitchens, garages, lofts, attics, cellars and basements .Note: ultrasonic waves cannot penetrate furniture, cabinets or walls: multiple units are required to protect multiple rooms .In order to be effective, a pest control effort needs to use several different tools and methods. First, rid your space of rats and mice using one of the many solutions offered by Victor; whether your preference is snap, electronic, live or poisons, there is a solution to fit your needs. After the rodents are eliminated, use the Victor pest chaser to keep them away.