Advanced Features and 2 Power Modes: Multiple sensors and receivers can be easily added if you want to monitor multiple entrances or areas. The receiver is an AC connector; the motion detector can be operated with 2 AAA batteries or with a USB cable. Detection area: Our wireless infrared motion detector can detect all movements within the detection area. If someone or animal is in the detection area (4-5m x 110°), the motion detector can detect a slight change with blue light alarm, then it immediately sends a signal to the receiver and the receiver plays the ringtone you selected and the LED lights up5 volume levels and 58 ringtones: The ringtone receiver has 58 melodies and 5 adjustable volumes from 0 to 110 dB. The ringtone is loud enough that you can monitor what is happening outside at all times. The LED bell is particularly suitable for the elderly and the hearing impaired. There are four indicators on the sensor, one red indicator for low power alarm and three blue indicators for alarm detection Two working modes: Our motion sensor detects every 1-2 seconds or 5-8 seconds (default setting). You can set the operation modes yourself according to your needs. Please note that the motion sensor is not waterproof. We therefore recommend that you install the motion detector on the inner roof of the door. In this way, the detection zone is vertical behind the door. When someone walks into a store or house, they walk in Easy installation: just plug the bell receiver into an outlet, for motion detectors you need to make a hole on the wall with a drill and attach the bell bracket motion detector with screws and anchors, then mount the other round part of the bracket, put motion detectors and detection Adjust it so that it is aligned with the area you have selected