The SA200-2B from Thorlabs Inc is a Dual Wavelength Fabry-Perot Interferometer that operates from 290-355 nm & 520-545 nm. It has a free spectral range (FSR) of 1.5 GHz and a frequency resolution of 7.5 MHz. This confocal, scanning interferometer has a cavity length of 50 mm, a typical finesse over 200 and it constitutes of ultrastable athermal invar cavity with a low scan voltage. The outer housing material of this interferometer is made up of black anodized aluminum. It has an inbuilt detector unit and is ideal for telecommunication and spectral analysis applications.