The OP508 was specifically designed for applications where cost-effective solutions for measuring, monitoring and logging of insertion loss or power fluctuations are needed. The OP508 is a small (4″x2″x1.25″) desk-friendly module designed such that minimal movement and bending of the reference and test cables is necessary. This results in stable, accurate and repeatable measurements. The OP508 is offered with various detectors and connector styles with a fixed optical interface covering a wide variety of applications. The USB powered module connects directly to the computer.OptoTest provides for drivers and applications allowing the user to perform common measurement tasks such as EXCEL data logging or time-stamped stability measurements
http://optotest.com/OP508.html
Bench-top test equipment, optical power meter