Excellent technology:It uses changing ultrasonic frequencies to stimulate and damage the auditory nervous system of mosquitoes/rats, making them unbearable, panicky and rushing to escape the house. Safe for Children and Pets: Using low frequency electromagnetic sound waves that cannot be heard by human ears and pets. No chemical ingredients, safe and secure. Wide Coverage: Each ultrasonic repeller provides 115 square feet of coverage, making it the perfect choice for your bedroom, bathroom, garage, kitchen, office and wherever you want to easily get rid of bugs. Product usage decreases after walking through walls or solid objects, we recommend using one unit per room for best results Easy to use: This electronic pest repellent can easily be installed in any environment. any outlet in your home or office. Rodent repellents should take several days to work effectively.