The FC F-M from FOCC Technology is a Fiber Optic Attenuator with Attenuation 1 to 30dB, Operating Temperature -40 to 75 Degree C, Optical Power w 200 mW, Polarization Dependent Loss 0.1 dB, Return Loss PC:50dB UPC: 55dB APC: 60dB. More details for FC F-M can be seen below.