[Alarm, Chime & Voice Ringtones 30 Tones, 5 Volumes] 30 ringtones, 5 volume levels (up to 110dB) for your door sensor chime: loud door alarms for home security, gentle door sensor chime for business, and door chime for when door opens with voice reminder.
[500ft Wireless Range & Expandable Pairing] This wireless door open chime and home offers 500ft open-area range, reliable 100ft indoors. Avoid metal doors and devices like microwaves/TVs.
Expandable: each receiver pairs with up to 9 sensors.
[Low-Power Battery] Powered by one AAA battery (included). This door sensor alarm consumes less power for fewer battery changes.