The SMC-1618 from Sierra Microwave Technology is a RF & Microwave Circulator with Frequency 16 to 18 GHz, Average Power Reverse 2 to 150 W, Insertion Loss 0.4 dB, Isolation 20 dB, Operating Temperature -54 to 125 Degree C. Tags: Coaxial Circulator. More details for SMC-1618 can be seen below.