The BLK-712N from Synergy Microwave Corporation is a DC Block with Frequency 1 MHz to 1 GHz, Insertion Loss 0.10 to 0.50 dB, Breakdown Voltage 2500 V, VSWR 1.10:1, 1.50:1. Tags: Module with Connectors, Inner DC Block. More details for BLK-712N can be seen below.