Make a huge difference
These work great. Using 2 for most rooms/circuits does the trick. The electrical noise everywhere in our house ranged from 100+ to as high as 250mv. Ideally it should be less than 30mv in every outlet. Most outlets in our home are now reading 20 or less. There are a few tricky areas I'm still working on  especially where we have a lot of electronics. I just ordered 4 more and will be adding a few to our garage. The seller is great and shipping is always quick, usually arriving early.
Rating: 5 stars