Wireless doorbell with a range up to 450' (137 m), 90 dB. Downloadable MP3 sounds. Illuminated halo and LED strobe alerts, 7 custom halo alert colors. Assignable halo and strobe alerts per push button and accessories. Adjustable volume, sleep mode and mute to adapt use for the time of the day. Mute timer 3, 6, 9 12 hours and permanent mute. High quality sound. Connect-up 6 transmitters simultaneously, such as push buttons and awareness devices (door contacts, motion sensors). Battery life up to 5 years. Easy to install, portable or wall mounted options (wall mounting kit included). ActiveLink robust signal. Requires 4 alkaline batteries, type C (not included). 1 year warranty.