The ISL-1 from MCLI is a RF & Microwave Isolator with Frequency 19.7 to 20.3 MHz, Average Power Forward 30 W, Average Power Reverse 10 W, Insertion Loss 1.3 dB, Isolation 17 dB. Tags: Module with Connector, Coaxial Isolator. More details for ISL-1 can be seen below.