Seems they are for cell phone use mostly/ideally. The Audiophile comments on their usefulness seems rather subdued and a tad less than completely enthusiastic. I get they are only 1/10th the size and I guess possibly 1/10th the effectiveness? Look forward to owner comments on use and actual effectiveness. I was thinking of placing them in smaller 5-12 VDC LPSs, USB reclockers/filters and speaker crossover boards. I think in the right application these cards may be a great little tweak. These smaller LPSs and USB filters/reclockers are very small in size and perhaps the card is all that is needed for maximum impact?