Toroidal Isolation Power Conditioner

I suggest reviewing the Equitech website for a significant amount of information.

Why does it have to be a toroid? They have wider bandwith, when with a filter you want the smallest bandwidth possible. Split bobbin EI or EI with interwinding shield makes more sense.

Isoclean PT-3030G. There is an ebay seller.

Ait. Please explain.

By their nature, toroidal transformers have a much wider bandwidth than EI transformers, meaning they pass more high frequencies than an EI would, while both will pass the fundamental AC frequency well (60 or 50Hz). The goal of an isolation transformer used as a filter is to block as much of the HF hash as possible, preventing it from getting into the connected equipment, so it stands to reason that a more lossy transformer would do a better job of that.

Not saying a toroid with an interwinding screen won't do a good job, but I don't see any reason to fixate on a toroid; an EI can do as well or better for filtering.