The QDDC-500-18000-K4 from Qualwave is a Dual Directional Coupler with Coupling 30 to 40 dB, Coupling Variation ±1.2 dB, Frequency 500 to 18000 MHz, Average Power 400 W, Insertion Loss 1 dB. Tags: Module with Connectors. More details for QDDC-500-18000-K4 can be seen below.