No markings to indicate particle collection efficiency but I'm not at all sure I would trust them if they did it would be I bought them because the original Kirby charcoal filter bags seem to be discontinued, the prices for leftover stock are inflated, and the original Kirby filters have performed better than the Kirby "HEPA+" bags. (Note: the original Kirby charcoal bags didn't claim to be HEPA either, but were still the best tested.) Given the price, I don't expect them to be as effective as…