These devices use ultrasonic or electromagnetic technology to emit high-frequency sound waves or alter the electromagnetic field, which is claimed to repel pests like rodents and insects. The device is designed to be plugged into an electrical outlet and is marketed as a safe and environmentally friendly alternative to traditional pest control methods such as poisons and traps. It is claimed to be effective against pests such as fleas, cockroaches, mice, insects, mosquitoes, ants, spiders, and bed bugs.