The PMOCIR-8-B from COMCORE Technologies is a Fiber Optic Circulator with Insertion Loss 1.8 to 2.1 dB, Isolation 22 to 30 dB, Operating Temperature -5 to 50 Degree C, Optical Power 300 mW, Return Loss 50 dB. More details for PMOCIR-8-B can be seen below.