High Sensitivity: The lens type optical strengthens the beam intensity, has good immunity to false alarms caused by rain, snow, fog, etc., highly convenient to use. Low Battery Reminder: When the battery is low, the red LED on the transmitter side will flash, and the receiver's buzzer will sound every second to remind you to replace the battery in time. Wide Applications: Provides infrared beams for automation applications such as sliding and swinging doors, garage doors and security applications, outdoor or indoor fencing, etc. Waterproof Infrared gate beam sensor is IP55 waterproof, can be installed indoors or outdoors, small size, easy to install, does not affect the normal function of your device. Structure: Infrared gate beam detector is made from superior ABS, wear resistant and durable, the transmitter is powered by 2PCS AA batteries (not included), and the long life can about 2 years.