With the innovative wireless bell DC915SL from Honeywell Home, you'll never miss a visitor again, thanks to a reliable wireless range of up to 200 meters and an audible range of up to 100 meters. The sleep mode silences the wireless bell for three, six, nine, or twelve hours, allowing you to relax without any disturbances. The innovative Halo light ring will alert you to the arrival of a visitor when the doorbell is not audible. With the built-in repeater/wireless amplifier, the wireless range can be extended to up to 400 meters by adding a second wireless bell. Battery life lasts up to five years.