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

The Oura Ring 4 is our choice as the best smart ring, and its Brushed Silver variant is on sale for the first time during Amazon's Prime Day at 15% off.

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.