New Applied Insecticide Riddex Plus Electronic Ultrasonic Household Residential Pest Mouse Rodent Control Repeller 220V Repells Rodents and Insects Product size:5*3*10cm Effective Coverage: 80-120m2 Uses state-of-the-art Electromagnetic & Ultrasonic technology Ambient temperature: 0 to 40 degrees Celsius Installed from the ground 20 to 80 cm, try to avoid carpets, curtains and other sound-absorbing material, to prevent the reduction of sound pressure to make sound field becomes smaller influence repellent effect; use within a few days ago, if found that mice, insects and other activities increased significantly, it is a normal phenomenon. Because usually hiding in the nest of rats, after insect attack by ultrasound and electromagnetic waves, have fled their original hiding place;