The downside to choosing a physics major in college is that you can never watch and action movie again without noticing all the things that happen that violate the laws of physics. Keep these observations to yourself. Because soon your family will refuse to watch movies with you. DAMHIK.
The upside to choosing a physics major is college is that you don't believe in black magic. So a black box that does things that aren't supported by physics doesn't interest you.
I bring this up because there is significant discussion in this thread about these appliances that the consumer certainly can't be capabile of understanding, but trust us, they remove noise.
Noise isn't like chunks that can be removed with cheese cloth. Once you have noise in your power, the best thing you can do is rectify it and invert it with a super high quality inverter.
And for those of you that think their suburban power is clean, mine runs about 4-5% thd.
Jerry