I bought the filter to try to eliminate occasional popping sounds and picture interference on my old Freeview box. To be fair I also fitted a graphite core to the mains lead (so part of the improvement could be due to that) but the combination of the two actions has brought about a 99% improvement. Just very occasional interference now and when the sound is affected it is not at loud volumes. I've also the added peace of mind of surge protection. I can't confirm that the picture or sound are otherwise improved - both are normally very good - they may be, but it is tricky to do a before and after. Certainly not worse anyway!
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