The E-964-S50TB is a simple, easy-to-use, and easy-to-install single-beam infrared motion sensor with 4 selectable frequencies. The device easily installs almost anywhere to provide an invisible beam that, when broken, sends a signal to activate a light, beeper, or other device. This makes the device perfect for use as part of an access control system, a door or window monitor, a retail store customer alert, or many other places where the user needs to know that someone has entered a specific room or building or other protected area. The E-964-S50TB is weather-proof, and comes with a built-in AGC control circuit that helps to filter out possible disturbance caused by local lighting conditions.