The C1-B77 from RD Microwaves is a Directional Coupler with Frequency 4 to 8 GHz, Coupling 6 to 30 dB, Coupling Variation ±1 to ±1.25 dB, Directivity 20 dB, Average Power 10 to 50 W. Tags: Module with Connectors. More details for C1-B77 can be seen below.