Magicfly Key Finder with 3 Receivers. Wireless RF Remote Item, Wallet Locator,Black Works through walls and floors; Long working distance,Transmitting Range:30~40 meters open space 15-20 meters (indoors); Loud sound:80~90Db; Frequency: 433.92MHz, Housing material ABS; Use to find keys, child, the aged people, wallet, purse, pets, dogs, and other items.