The DC-490-180 from RF & Noise Components is a RF & Microwave Circulator with Frequency 480 to 500 MHz, Average Power Forward 250 W, Insertion Loss 0.3 to 0.35 dB, Isolation 20 to 23 dB, Return Loss 20 to 23 dB. Tags: Drop-in Circulator. More details for DC-490-180 can be seen below.