The 137 Series Optical Thickness Gauge includes a super-luminescent LED (SLED), an interferometer assembly, and a digital processor, all housed within a single chassis. It is able to provide accurate results within ± 1 µm (± 0.04 mils), and exceptional repeatability (standard deviation) as good as ± 0.05 µm (± 0.002 mils), to ensure that the measurements are well within the specified accuracy limits. With a rugged design and free upgrades for the software, these gauges are ideal for applications in manufacturing environments.