The T3XB4 from Sonoma Scientific is a RF & Microwave Isolator with Frequency 3.7 to 4.2 GHz, Average Power 10 W, Average Power Forward 10 W, Insertion Loss 0.4 dB, Isolation 20 dB. Tags: Module with Connectors, Coaxial Isolator. More details for T3XB4 can be seen below.