The 990-370390-301 from M2 Global Technology is a RF & Microwave Circulator with Frequency 3.7 to 3.9 GHz, Average Power Forward 50 W, Insertion Loss 0.35 dB, Operating Temperature -40 to 85 Degree C. Tags: Drop-in Circulator. More details for 990-370390-301 can be seen below.