BLK-89-S+ SMA DC Block Mini-Circuits BLK-89-S+ SMA DC Block offers a 0.1MHz to 8000MHz frequency range, up to 0.9dB insertion loss, and 13dB to 40dB return loss range. This DC block features broadband performance, low insertion loss, rugged unibody construction, and off-the-shelf availability. The BLK-89-S+ comes in an FF888 case style with an SMA connector. Mini-Circuits BLK-89-S+ SMA DC Block is ideal for use in communication systems, defense systems, and test and measurement instrumentation.