The JCC3700T4200N2 from JQL Electronics is a RF & Microwave Circulator with Frequency 3.7 to 4.2 GHz, Average Power Forward 20 W, Insertion Loss 0.4 dB, Isolation 20 dB, Operating Temperature -40 to 75 Degree C. Tags: Coaxial Circulator. More details for JCC3700T4200N2 can be seen below.