The ZDC-20-3-75-1 (+) from Mini Circuits is a Directional Coupler with Frequency 55 to 90 MHz, Coupling 18.61 to 18.70 dB, Directivity 30.28 to 34.58 dB, Power 4 W, Average Power 4 W. Tags: Module with Connectors. More details for ZDC-20-3-75-1 (+) can be seen below.