The DC-515-183 from RF & Noise Components is a RF & Microwave Circulator with Frequency 470 to 560 MHz, Average Power Forward 250 W, Insertion Loss 0.4 to 0.5 dB, Isolation 20 to 21 dB, Return Loss 20 to 21 dB. Tags: Drop-in Circulator. More details for DC-515-183 can be seen below.