EASY TO INSTALL: 2 transmitters included, wireless installation possible on a wall, 4 screws included, 4 dowels, 1 key and two double-sided adhesive strips. EXTRA LONG WIRELESS SIGNAL RANGE 400 M/1,300 FT: Without interference from other electronic equipment in your house or those of your neighbours. So make sure you never miss a visitor, even if you're on another floor or several rooms away from your front door. 52 CHIME AVAILABLE: The 40mm stereo speaker produces a rich and clear sound, 52 melodies available and 5 adjustable volume levels with a maximum output of 115 dB. You can choose a different ringtone for each transmitter and thus know which of your doorbells has been triggered. HIGH PERFORMANCE TRANSMITTER: Very low power consumption, CR2032 lithium battery with 3 years of maximum life. Dust resistant and IP55 waterproof. Operates between -20 and 60 and withstands harsh weather conditions. MEMORY FUNCTIONALITY: The device remembers the last sound and volume settings after a power outage. You won't need to adjust your settings again. Convenient and easy to use for an optimized user experience.-