Use physical method, non-toxic, no harm to human beings or pets. Small size, won't take much space. The frequency of the ultrasound wave and electromagnetic wave is changing intermittently and constantly, so mice and insects will not become adaptive to a certain fixed-frequency. Powerful: the effective protection range is about 150 square meters under open environment. With night light, the soft and warm blue LED light can protect your eyes from being stimulated suddenly by strong light at midnight. Mainly applied to repel mice, mosquitoes and cockroaches, also can be used to repel and control other pests like spiders, ants, bugs.