... 3.good function and nice design 4.long lifetime Indoor Electronic Ultrasonic Rat Mosquito Insect Repellent RC-503A Features and ... life operationMain CausionIt applies to the places which like home,restaurant,warehouse,building,farm,hospital,office,machine room,hotel, ... do harm on the mosquito repelling effect..Packing information Home Protect Indoor Electronic Ultrasonic Rat Insect Repellent RC 503A