The C1-C28-20 from RD Microwaves is a Directional Coupler with Frequency 2 to 8 GHz, Coupling 6 to 30 dB, Coupling Variation ±1 dB, Directivity 18 to 20 dB, Average Power 10 to 50 W. Tags: Module with Connectors. More details for C1-C28-20 can be seen below.