The BLK-18-S+ from Mini Circuits is a DC Block with Frequency 0.01 to 18 GHz, Insertion Loss 0.02 to 1 dB, Breakdown Voltage 50 V, Return Loss 12 to 36 dB, Operating Temperature -55 to 100 Degree C. Tags: Connectorized, Inner DC Block. More details for BLK-18-S+ can be seen below.