This is a reflective infrared sensor that can be installed with one-side wiring saves installation time and cost. As wiring is needed only on the sensor unit (one side), you can use it in places where it is difficult to wire on both sides. One-side wiring reduces time and cost of installation significantly. This sensor can be used both indoor and outdoor. 2-Types of attenuation sheets (for indoor and outdoor) are attached. Beam alignment can be adjusted on the sensor unit side only by utilizing viewfinder, attached attenuation sheets and alarm LED. It has a unique ambient light compensation circuit and special filters to obtain a strong immunity to ambient light such as sunlight, vehicle headlights and mercury light. Using the adjustments, the lens can move horizontally (more less 90°) and vertically (more less 10°) allowing the unit to work in all directions. Response time can be adjusted by the response time adjustment potentiometer. (0.05-0.7 s) Operation check can be done quickly with alarm LED (red).