The C1-A0518-20 from RD Microwaves is a Directional Coupler with Frequency 500 MHz to 18 GHz, Coupling 20 dB, Coupling Variation ±2 dB, Directivity 10 to 22 dB, Average Power 10 to 50 W. Tags: Module with Connectors. More details for C1-A0518-20 can be seen below.