The T3ZJ4 from Sonoma Scientific is a RF & Microwave Isolator with Frequency 3.4 to 4.2 GHz, Average Power 0.5 W, Average Power Forward 0.5 W, Insertion Loss 0.4 dB, Isolation 23 dB. Tags: Module with Connectors, Coaxial Isolator. More details for T3ZJ4 can be seen below.