For household models, the individual part number is 049258AG. The retail two-pack is 40201048 (also labeled as a "Type 48" belt)
044783AG (AH20075 as a two-pack) is the belt for industrial uprights. This has the same dimensional fit, but uses a different rubber compound that is supposed to be better suited to heavy commercial use. But the industrial belt should work fine in a household cleaner.
I personally do not trust Amazon to supply genuine parts. Amazon warehouses often mix up stock from different suppliers. I can sometimes find genuine Hoover household Type 48 belts at local Ace hardware stores, but generally I have to get them from a vacuum shop.