The IS-37 from MCLI is a RF & Microwave Isolator with Frequency 1.29 to 1.39 GHz, Average Power Forward 5 W, Peak Power Forward 0.2 kW, Insertion Loss 0.5 dB, Isolation 20 dB. Tags: Module with Connector, Coaxial Isolator. More details for IS-37 can be seen below.