RADIO SHACK SELL A SINGLE OUTLET COMPUTER SURGE AND NOISE FILTER IT HAS A 45DB NOISE FILTER BUILT INTO THIS DEVICE I BOUGHT TWO TODAY PLUGED THEM INTO A GROUNDED 3 WIRE AC OUTLET AND WAS SHOCKED TO SEE ALL MY AC LINE NOISES DISSAPPEARED THE RADIO SHACK PART# IS 61-2215 14.99 EA ALL THE BEST RAY NR1R