Reliable Range: The sensor transmission range detects movements up to 280 m and the infrared sensor detection range about 2~8m to keep you alerted effectively. When motion is detected by the sensor, the receiver will make an audible sound and the LED light will flash. Different Melodies and Volume for Choice: The receiver is a doorbell design with 36 ringtones and 5 welcome bell sounds for your personal preference. Wide Application: You can place the receiver in your home and put the infrared motion sensor in other places, such as home mailbox, driveway, porch, gate, door, walkways, door entrance, apartment, office, hotel, store and many other indoor places, not suitable for outdoor; the motion sensor door chime without waterproof function.