We've got big rolls of 36 gauge copper foil at work, so I've tried cutting strips of this to experiment with. With foils, you can add layers to try different amounts of shielding. It can be tightly wrapped & pinch formed to close around the back of the ac plug. I must say I do hear some changes to the sound of the cd player & dac with added shielding on the iec plug. I'm not sure that I like what it does on my Marantz Sa11S1, but it's a definite positive used on my dac.