Safe uses devices with intensity of high frequency sound waves to chase away rodents. The devices are very safe, clean, and easy to install. They can also be installed in sensitive and cold storage areas.
Ultrasonic Rodent Repellers are electronic transmitters of high frequency sound (well above the 20 KHz frequency which is the upper limit of the hearing range of the human ear). They emit intensive sound at high decibel levels (sound pressure) that is audible and painful to pests but is inaudible and harmless to humans. The pests will usually leave the area being protected by the ultrasound. They do not get killed.
The powerful sound waves generated by the transducers of repellers are within the hearing range of many pests and cause them pain and discomfort. Sometimes they will leave the area being protected immediately, in other cases it will take as long as two to three weeks before significant reduction in infestation occurs.