This Portable Wireless Doorbell has a high-quality sound that comes with 8 tunes and has a range of 450 ft. (137m) and a sound level of 90 dB. It has a downloadable MP3 with unlimited downloadable tunes. It has illuminated Halo and LED strobe alerts, including 7 Custom LED halo alert colors and assignable halo and strobe alerts per push button and accessories. You can conenct up to 6 transmitters simultaneously, such as push buttons and awareness devices (door contacts, motion sensors). It is an easy installation with a portable or wall mount option, with a wall mounting kit included. The weather resistant, surface mount, Push Button has an illuminated Halo LED feedback and Wireless "E" Push-button compatibility. 1) Battery Life of the doorbell is up to 5 years, 2) Honeywell ActivLink robust signal, 3) Doorbell requires 4 C alkaline batteries (not included), 4) The CR2032 battery for the Push Button is included, 5) Adjustable volume, sleep mode and mute (Mute timer 3, 6, 9, 12 hrs and permanent mute) to adapt use for time of day. Grey.