The ST-711C-3 from Sintec Optronics is a Fiber Optic Isolator with Isolation 28 to 30 dB, Operating Temperature -5 to 50 Degree C, Optical Power 5, 10, 20 W, Polarization Dependent Loss 0.1 dB, Return Loss 50 dB. More details for ST-711C-3 can be seen below.