Even a trivial filter inside a Ul power strip was just enough filtering to cause noise reduction. That does not for one minute say that filter is effective because a 'glass of water' filter (inside the Ul power strip) is made irrelevant by an 'electric pump sized' filter that should have been inside that power supply. Of course EMI/RFI filtering that John Smith was touting to protect appliances is totally irrelevant to the original poster's question. But John Smith touted it as if it was some major improvement - which the filter is not. Once numbers were applied, power cord filter does nothing significant - as demonstrated by the filter that was suppose to be inside your power supply. Purpose of that filter inside a power strip protector is for a UL1449 requirement - that is also completely irrelevant to this thread. Personally, I use the 10 outlet strips from SL Waber, or Belkin, which have 5 duplex outlets side by side.. with a little bit of planning, you can fit 6 rather large wall warts, and 4 regular power cords on a 10 outlet strip. I currently have 2 of these mounted on the brace underneath the back of my desk, one for UPS power from the rack mounted UPS in the server closet, and one for non-UPS power. Both the UPS, and the non-UPS power are fed from a master Ul power strip, so the total load is limited by the 15 amp breaker in the master Ul power strip. It's a conspiracy. Every cheap Ul power strip I can find in the stores have the AC connectors in-line with the Ul power strip. That limits the number of wall warts (power adapters) that can be installed to perhaps two or three. This year, I have to buy twice as many Ul power strips to power the typical home computah. Last year, there were almost identical Ul power strips available, but with the AC connectors perpendicular to the strip, which would allow for 3-5 wall warts. This year, if I want to purchase a Ul power strip with perpendicularly oriented plugs, I have to pay something like 5 times the price of the inline strip.