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.

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

Amazon Prime Day is happening July 8 through July 11, and it's one of the best online sales events of the year. Whether you're looking forward to getting a good deal on new tech, home goods or anything in between,