What’s the catch? This is the best deal I can find on the internet by a fair margin. This seller has an amazon store page as well and seems to have a good reputation on both. The seller claims its a new HDD from a reputable brand and offers a 5 year sellers warranty.
I looked into this before with a similar deal by a 3rd party seller on Amazon. The enterprise drives (I was looking at those EXOS drives, too) must be sold by the manufacturer certified reseller or you run the chance of getting zero warranty. That being said, I’ve seen plenty of conflicting stories by people that bought them and needed to submit an RMA. I’d say it was a 60/40 split of honoring the warranty to not honoring it.
Long story short, it’s a gamble. They’re likely good drives, but you’re rolling the dice if something goes wrong with them.