The SMC-2640 from Sierra Microwave Technology is a RF & Microwave Circulator with Frequency 26.5 to 40 GHz, Insertion Loss 1 dB, Isolation 14 dB, Operating Temperature -54 to 85 Degree C, Storage Temperature -54 to 85 Degree C. Tags: Coaxial Circulator. More details for SMC-2640 can be seen below.