I had the opportunity to try a number of Jensen inductors during the modding of my speakers. I had already had good results with the Jensen 4-pole capacitor filters. The inductors are copper-foil with oil-impregnated paper dielectric. They are about 1" wide 12 gauge coiled copper foil and range in size from about 2" to 6" in diameter for my speakers.
I had previously purchased one set of 6mH (large) Alpha-Core inductors to try on the Bass speakers of my reference KEF 104/2's. These took a week or so to break-in because they have Polypropylene dielectric. The Alpha-core inductors improved both the Bass impact and high-frequency clarity significantly, but my wife was convinced that the bass viol still had some flab to it.
After replacing the Alpha-core inductors with the Jensens, it was immediately obvious that the bass flab was gone. Plucked notes were extremely clear and defined now. The high-frequencies, particularly the cymbols also became even more crystalline and clear. Very lifelike. Highly recommended. They sell direct to US customers because they have no US distributor. I am considering becoming a distributor for these.