The 1550-1-B-30-PM-M from CivilLaser is a Fiber Optic Attenuator with Wavelength Dependent Loss <1 dB, Attenuation 0 to 30 dB, Insertion Loss <1.5 dB, Polarization Dependent Loss 0.5 dB, Operating Wavelength 1550 nm. More details for 1550-1-B-30-PM-M can be seen below.