Power Strip. I have 3. One for each of the 3 circuits used for my system. The QB4 has 4 outlets. 3 of the outlets have resistors installed. Nordost states that the resistors slightly lift the ground - and also serve to lightly separate the circuits from each other to prevent cross-contamination from the other components that are plugged into it.
I'm not a fan of the resistors. I only use the primary earth outlet in two of the QB4's. In the 3rd one, I disconnected the resistors - so that all of the outlets are primary earth. In my system, the resistors sound less dynamic.