I'm not sure how it works. It's a passive thing, and doesn't require power. No battery.Isn't that gizmo meant to add impedance "back"? I though it was to add the missing impedance that wireless systems don't have that an instrument cable does.
Or maybe it does both?
To my ears it is like a presence control on an amp. I just use it with passive p/ups and an instrument cable, and set it how it sounds best.
You can ask Radial about it here..
Dragster FAQ - Radial Engineering
When I bought mine, the description on their site mentioned it would help with long cable runs but I don't see it there now.

My tech is actually making me a solid one piece Mahogany body for the neck that I will just do a natural oil finish on it without a pickguard. I have a cream DiMarzio model P pickup with a Nordstrand 2b preamp that I am going to install in it. I ended up using the Spalted Maple pickguard, and relentless pickup/controls from the Black mini and put it on the little Red. I'll use the chrome Hipshot hardware from the Black mini on the replacement Mahogany body. Here is a pic below of the new Mahogany mini body in progress. He was going to be done with it by now but we had a full month of 110+ degree weather here in Vegas and it was a bit to hot for the Tech to be in his garage with his wood working tools. He said he should be getting back to it in the next few weeks when it drops down below 100...Desert summers are not fun.