Amid this growing threat, Amazon made crucial changes to its annual Prime Day sale, which started on July 8, to attract more customers. First, it extended the sales event to four days; last year it was only two days long. Amazon has also ramped up advertising of the event’s steep discounts.

Amazon Prime Day can be a great time to pick up new tech, kitchen gear, and pretty much anything else you can think of on sale — but it might just be an even better time to buy refurbished products.

If you’re a Prime member, you can save up to $100 on the waterproof e-readers.