The QBDC-4000-6000-K4-40-NS from Qualwave is a Bi-Directional Coupler with Frequency 4 to 6 GHz, Coupling 40 dB, Coupling Variation ±1.5 dB, Average Power 400 W, Power 400 W. Tags: Module with Connectors, Bi-Directional Coupler. More details for QBDC-4000-6000-K4-40-NS can be seen below.