The Optek Optical Sensor - Photointerrupters - Slot Type - Logic Output OPB991L55Z is an optical sensor designed for use in a variety of applications. It features a 3.18mm slot type design with a logic output. This sensor is capable of detecting objects up to 3.18mm in size and can be used to detect the presence of objects, detect the passage of objects, and measure the speed of objects. It is also capable of providing a logic output signal when an object is detected. This sensor is ideal for use in applications such as industrial automation, robotics, and machine vision. It is also suitable for use in medical and automotive applications.