The PIOC3 from Flyin Optronics is a Fiber Optic Circulator with Insertion Loss 0.6 to 0.8 dB, Isolation 40 to 50 dB, Operating Temperature -10 to 75 Degree C, Optical Power 500 mW, Polarization Dependent Loss 0.15 dB. More details for PIOC3 can be seen below.