Wireless Door Chime, Security Door Open Sensor, Door Entry Alert for Home, Office & Store (500ft Operating Range, 52 Chimes, 4 Volume Levels), 1 Wireless Receiver 2 Window Open SensorAbout this item【Excellent Working Range】 Our wireless door chime working range up to 500 ft. Far enough to cover every door and window in your house.【50 Music with 4 Volume Levels】 Our door entry alert has 4 levels of adjustable volume. 50 unique chimes allow your wireless door and window entry alert system to meet any need.【Easy Installation】 Plug the receiver into any standard outlet. Tear the double-sided tape and stick the sensors to the door or window. The receiver will alert immediately when the sensors are separated.【Reminder Function】 If your door or window is left open. The receiver will ring every 5 minutes, and auto-silence after 5 times. You can turn off this function if you don't need it.【Expandable Wireless Door Chime】 You can add more receivers and sensors in multiple areas. Each wireless doorbell receiver can pair up to 50 sensors and each sensor can add unlimited receivers.