The KE-QA plug is like a PS Audio Noise Harvester on steroids. Using Quantum Resonance Technology and some really complex circuitry internally, the KE-QA plug had a more resounding impact in our electrical line than the PS Audio Noise Harvester. The “intensity control” allows some controls and adjustment to vary the effect in your system which the Noise Harvester doesn’t offer. This proved to be quite useful as you can tone it up or down to suit your listening preference. Final effects can vary greatly between homes and the electrical grid. For our store, which resides in a build where there are commercial and residential tenants, the electrical current can be rather “noisy”. The Noise Harvester did reduce somewhat the “noise” but the KE-QA was superior.
There are a lot more interesting reads on this topic which you can get from Kemp Electronics website or just google EMI/RFI interference. Cosmetically, the unit is in very nice shape. Original box and literature included.