The IS-137 from MCLI is a RF & Microwave Isolator with Frequency 5.2 to 5.8 GHz, Average Power Forward 1 W, Insertion Loss 0.8 dB, Isolation 15 dB, Operating Temperature -10 to 60 Degree C. Tags: Module with Connector, Coaxial Isolator. More details for IS-137 can be seen below.