Maybe someone here knows the answer - I can't find it. I found some blades on E-bay with the model name on them "Gold Test" and a logo of what looks like a "CF". There's some other writing on the blade but I can't make it out it's too fuzzy - I can't even tell if it's letters or numbers. Wilson has a Gold Seal and MK has a Gold Star, but none of the brands I can find online sell a Gold Test. The winning - and only - bid was mine for the large sum of... 99 cents. So whatever they are, junk or not, they cost me 8.99 which includes the $8 shipping charge.