RPR220 is an integrated reflective photoelectric sensor transmitter is a gallium arsenide infrared emitting diode while the receiver is a high sensitivity silicon planar phototransistor mainly used in game machines copiers and office automation equipment. Features: 1. Plastic lens in order to improve the sensitivity; 2. Built-in visible light filter to reduce the impact of discrete light; 3. Small size compact structure; 4. Transmitters and receivers have two pin-out which is the positive long-legged short leg is negative.