Conveniently, Prime Day fitness tracker deals (all four days of them) drop right in the middle of summer, which makes this a great time to pick up the smartwatch or smart ring that you just didn't have the cash for at Christmas. The Best Fitness TrackerFitbit has faced pretty stiff competition over the years (most notably from the Apple Watch), but its flagship Charge line is still the best overall fitness tracker for the money. The Best If You Have an iPhoneThe Apple Watch Series 10 is the best fitness tracker for iPhone users. It still doesn't have blood oxygen sensing due to a patent dispute, but it's otherwise a solid fitness tracker. The Scanwatch 2 follows in that tradition with a comprehensive suite of health features and Withings' new cardiac-focused health features, like Cardio Check-Up, which lets you send your cardiac data instantly to Withings' board of certified cardiologists.