'- Solar powered wireless infrared break beam system that is simple to install and requires no wiring- Break beam sensors are powered by lithium ion batteries that are recharged through the solar panels during the day- Infrared sensing terminals can be mounted up to 300 feet apart and will send a signal back to the DCR-2500 receiver up to half mile away anytime someone passes between the sensors- Will not be activated by any motion outside of the monitored beam- Sensors are not affected by small objects such as falling leaves or birds- Ideal for outdoor applications such as storage lots, lumber yards, car dealerships, etc.- Multiple sensor pairs can be used to send a signal to one receiver if you wish to set up a perimeter