The QDDC-20-520-50-50-S from Qualwave is a Dual Directional Coupler with Coupling 50 dB, Coupling Variation ±1 dB, Frequency 20 to 520 MHz, Average Power 50 W, Insertion Loss 0.35 dB. Tags: Module with Connectors. More details for QDDC-20-520-50-50-S can be seen below.