The DC-495-181 from RF & Noise Components is a RF & Microwave Circulator with Frequency 490 to 500 MHz, Average Power Forward 250 W, Insertion Loss 0.3 to 0.35 dB, Isolation 23 to 25 dB, Return Loss 23 to 25 dB. Tags: Drop-in Circulator. More details for DC-495-181 can be seen below.