High performance TRANSMITTER: consumes very little current; uses a CR2032 type lithium battery which provides a maximum of 3 years of service; Ingress Protection Rate (IP) 55, well protected against dust and water; operation at temperatures between -20 and +60C; withstands extreme weather conditions 52 BEAUTIFUL MELODY: 40mm stereo speaker delivers rich, crystal-clear sound; to choose a melody, press the "Next" or "Previous" button; 5 adjustable volume levels, with a maximum of 115 dB; you'll hear pleasant melodies every time the doorbell rings WIRELESS RANGE OF 400 METERS (1312 FEET): 1 receiver to plug into power outlets are included; the chime does not interfere with other equipment in your home or your neighbors; never miss any of your visitors, even if you are several rooms away from your entrance MEMORY FUNCTION: it keeps in memory your last choice of melody and the volume selected after a power cut; no need to reset your previous settings; practical and easy-to-use device for better user convenience EASY to install: the set includes: 2 screws, 2 dowels, 1 key, 1 adhesive tape for easy installation of the transmitter< /p>