It looks like they took it from this listing instead (the number of ratings matches up):
With that one, the price is higher which makes Woot’s price much lower in comparison. But the one you found appears to be the same product at a lower price.
(Please note: I don’t work for Woot, I just volunteer to help out here on the forums.)
Hi! Yes, according to the original Amazon listing this is an 8 pack - which explains the difference in price.