The Optek OPB616 Slot Type Logic Output Photointerrupter is a reliable and cost-effective optical sensor designed for use in a variety of applications. This sensor features a 3.81mm PCB mount and a logic output, making it ideal for use in a wide range of applications. The OPB616 is designed to detect the presence of an object in a slot or gap, and can be used to detect the presence of a moving object, such as a conveyor belt. The sensor is also capable of detecting the presence of a stationary object, such as a paper or card. The OPB616 is designed to be easy to install and use, and is capable of providing reliable and accurate results. The sensor is also designed to be resistant to environmental factors, such as dust and moisture, making it suitable for use in a variety of environments. The OPB616 is an ideal choice for applications requiring reliable and cost-effective optical sensing.