The COF-2040 from Stellant Systems is a RF & Microwave Circulator with Frequency 2 to 4 GHz, Insertion Loss 0.5 to 1 dB, Isolation 17 to 35 dB, Operating Temperature 0 to 55 Degree C. Tags: Module with Connector, Coaxial Circulator. More details for COF-2040 can be seen below.