Yes, it works good.Never seen one of these before. Do they actually work?
It will only eliminate one single noise source at a time. I used it to eliminate the most annoying noise.
You have to install a second antenna to phase the noise out. I have good luck with the two antenna feed points close together and the two wires 90 degrees from each other. The noise antenna parallel with the house and the main antenna perpendicular to my house. You may need to experiment with the noise antenna to receive a good signal from the noise source. It may only need to be a 10' wire depending on how local the noise source is.
The Timewave ANC-4 is a similar noise eliminator you may want to consider. MFJ's quality control isn't so great so you may get a bum unit. I got lucky and have one with no problems.
I use the DX Engineering NCC-2 now but it is much more expensive.