The ZX30-20-4-S+ from Mini Circuits is a Directional Coupler with Frequency 5 to 1000 MHz, Coupling 20.5 dB, Coupling Variation ±0.6 dB, Directivity 11 to 21 dB, Average Power 1 W. Tags: Module with Connectors. More details for ZX30-20-4-S+ can be seen below.