The BLK-711N from Synergy Microwave Corporation is a DC Block with Frequency 3 to 500 MHz, Insertion Loss 0.04 to 0.20 dB, Breakdown Voltage 2500 V, VSWR 1.08:1, 1.25:1. Tags: Module with Connectors, Inner DC Block. More details for BLK-711N can be seen below.