The ZDDC-50-521+ from Mini Circuits is a Dual Directional Coupler with Coupling 50 dB, Coupling Variation ±1 dB, Frequency 20 to 520 MHz, Average Power 300 to 400 W, Insertion Loss 0.05 to 0.25 dB. Tags: Module with Connectors. More details for ZDDC-50-521+ can be seen below.