The C1-B03 from RD Microwaves is a Directional Coupler with Frequency 1 to 12.4 GHz, Coupling 30 dB, Coupling Variation ±1 dB, Frequency Sensitivity 0.70 to 1.5 dB, Directivity 13 to 20 dB. Tags: Module with Connectors. More details for C1-B03 can be seen below.