The C1-C27-20 from RD Microwaves is a Directional Coupler with Frequency 1 to 4 GHz, Coupling 6 to 30 dB, Coupling Variation ±1 dB, Directivity 21 to 23 dB, Average Power 10 to 50 W. Tags: Module with Connectors. More details for C1-C27-20 can be seen below.