Wireless Infrared Detector: Motion sensor alerts can notify you of intruders or visitors. It detects motion and sends a wireless signal to the receiver, so you can always understand the situation and ensure safety. The infrared sensor's detection range is about 13-26 feet (4-8 m), and the maximum working range is 918 feet (280 m). Multifunction Sensor Chime: The sensor has Welcome/Alarm/Doorbell/Color Light and Night Light modes. 36 ringtones in doorbell mode to meet your needs. The 4-level adjustable volume/brightness, mute and color modes are suitable for the hearing impaired. Easy Installation: The doorbell can be charged via USB or installed with batteries to work better. No wiring required, no installation hassle, self-adhesive installation, the detector is mounted on the wall. The infrared sensor can rotate 360 degrees left and right and 180 degrees up and down. Expandable Wireless Pir Motion Sensor: Each receiver of the infrared sensor for alarm motion detection can be used