There are also fake Denso sparkplugs, fake Honda air filters, and who knows what else. Let the buyer beware.
This from one reviewer for a Amazon Honda air filter:
This product is listed as genuine Honda, but it is not. It ships from China with a Honda sticker on a plastic bag. Please look at the three photos which compares my OEM Honda filter to the new "Genuine Honda filter" to see why it is obvious this is not a Honda part. The first picture it is clear to see that my OEM includes the Honda name stamp whereas the "Genuine" filter does not. Also, notice the terrible finish on the edge of the filter (bottom-right). You can see where the plastic looks like it is cut...not Honda quality. The second image shows a difference in the bottom of the filters. My OEM filter (right) has a defined angled edge, the "Genuine" filter has a different angle.