2C3D AC Power Cord contains a patented Filter Pole system that works in Parallel (not series) with the AC, so it literally cannot limit current, but is very effective at cancelling noise. 2C3D AC Power Cord Includes Switchable Extended EM technology, which stands for Energy Management, and is Bruce Brisson’s newest development in technology surrounding the Power Products field. Put simply, E.M. allows energy to be more available consistently over the wide range of audio frequencies.