Mini Beam Sensor
This sensor is ideally suited for water drop photography. It will detect anything that passes between the ends of the sensor arms. The Miniature Beam Sensor includes a 6ft (2m) 3.5mm cable and plugs directly into the sensor jack of StopShot and StopShot Studio. It is much smaller and lighter than the full size beam sensor.
The opening for this sensor is: 2.01in (51mm) across x 1.15in(29.2mm) deep. The mounting screws are 2.5in (63.5mm) apart.