DC Blocks are coaxial components that prevent the flow of direct current (DC) while offering minimum interference to RF signals.
They have series capacitors on the input and output of the attenuator that allows RF signal to pass but block DC from passing through.

DC-6GHz N 100V DC Block Technical Specifications
Norminal Impendance	50ohm
Frequency range	DC-4/6/8/12/18GHz optional
VSWR	4GHz≤1.2 4-8GHz≤1.3 8-12.4GHz≤1.4 12.4-18GHz≤1.45
Power rating	2W
Temperature range	-45℃ to 85℃
Maximum Voltage	100V,200V optional
Insertion Loss	4GHz≤0.2dB 4-8GHz≤0.3dB 8-12GHz≤0.5dB 12-18GHz≤0.8dB