The product adopt an electromagnetic wave , ultrasonic imitates pair to expel parasite, expelling parasite area amounts to 100 m2, comparatively the low frequency pulsation type perturbation motion magnetic field, make the mouse physiology function disorderly, the fecundity destroying a mouses achieves run quickly completely exterminate a mouses purpose thereby. But ultrasonic an audible signal that it launches to the vicinity can be full of the entire room, system affecting vermins sense of hearing grave, make their creation fidgety and discomposed, flee from a scene thereby.