The SMC-2040 from Sierra Microwave Technology is a RF & Microwave Circulator with Frequency 2 to 4 GHz, Insertion Loss 0.4 dB, Isolation 20 dB, Operating Temperature -10 to 65 Degree C, Storage Temperature -10 to 65 Degree C. Tags: Coaxial Circulator. More details for SMC-2040 can be seen below.