The QDDC-400-450-20-40-S from Qualwave is a Dual Directional Coupler with Coupling 40 dB, Coupling Variation ±1 dB, Frequency 400 to 450 MHz, Average Power 20 W, Insertion Loss 0.3 dB. Tags: Module with Connectors. More details for QDDC-400-450-20-40-S can be seen below.