Crescent Premium Portable Wireless Doorbell Model B7 - Operating At Over 300 Meters Range - 52 Melodies Stereophonic - No Batteries Required for Receiver - 4 Level Volume Adjuster - Bionic Button OPERATING RANGE 300 meter of barrier free of receiving range, Remote transmitter button is rated IP44 weatherproof which can be used outdoor. ELEGANT MELODIES with 52 options to choose, chime type is stereophonic which gives impressive audibility EASY INSTALLATION of Transmitter with screws or double sticker included in the package EASILY PLUG RECEIVER into an electrical outlet (no batteries required for main receiver). CE, FCC, RoHS certified. CLASSIC DESIGN made with precision high quality durable material