Explanatory notes
… poor flexibility, high cost, etc., render natural mica unsuitable for many uses, it is frequently replaced by … of windows for ovens, stoves, furnaces, etc., of unbreakable lamp “glasses”, and of “glasses” for goggles, … other mica insulating parts of electrical apparatus, even unmounted, fall in headings 85.46 to 85.48 , and that mica …