The Variable-SM Series from Huihong Technologies Limited is a Fiber Optic Attenuator with Attenuation 2.5 to 65 dB, Attenuation Resolution 0.05 - 2.5 dB, Operating Temperature 0 to 40 Degree C, Return Loss 35dB (typical value 40dB), Wavelength 1260 to 1650nm. More details for Variable-SM Series can be seen below.