The C1-C27-XX from RD Microwaves is a Directional Coupler with Frequency 1 to 4 GHz, Coupling 6 to 30 dB, Frequency Sensitivity ±0.50 dB, Directivity 21 to 23 dB, Average Power 5 to 50 W. Tags: Module with Connectors. More details for C1-C27-XX can be seen below.