The wireless remote control doorbell is developed by adopting novelty decoding circuit design. It is of low duplication code rate and long transmission distance. It is efficient and practical and is easy and convenient for you to install and operate. You can put it anywhere because of its loud volume. You can choose either acousto-optic function or flashing function to inform you of guests arrival. It is widely used in many places, such as at home, in office buildings, in factories, in reception rooms and so on. The product HS-601 has a special design, modern and fashion, small and artistic, and is of convenience to use. Technical Parameter: Spacious distance: 80mFrequency: 433.92MHZ Tinkling of bell: 16 different pieces of musicFunction: Switch function between acousto-optic function and flashing (silent) function Power source: emitter:DC12V/23A receiver: three DC1.5V/AA batteriesSize: emitter:94×42×25mm receiver: 139×62×30mm