Jawbone Up2, Up3, Up4: What's the Difference?

In the past year, Jawbone has done some serious revamping of its Up fitness tracker line. Today, the company continues by announcing a duo of new activity trackers: the Up2, the successor to the Up24 band, and the Up4, a sister to the long-awaited Up3 tracker that also supports NFC payments for American Express cardholders. If you're thinking of purchasing a Jawbone tracker to get healthier, here are the small, yet important, differences between the newest products.

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Not only will the Jawbone Up4 be the first fitness tracker to support NFC payments, but it will also be the most premium product Jawbone has offered to date. In addition to the typical activity tracking abilities, the Up4 will also have the new "bioimpedance" sensors that the Up3 comes with, which can monitor resting heart rate, respiration and galvanic skin response.

Like the rest of the Up fitness family, the new Up2 and Up4 will use Jawbone's Up app for iOS and Android, which also has food logging features and the new Smart Coach system. Smart Coach builds on the information cards that the Up app has had for a while, learning your habits and lifestyle and suggesting tips and tricks to make you healthier.

Jawbone's data-based, personalized approach has always help the company set itself apart from other fitness wearable companies like Fitbit, which only show you your data rather than giving you ways to act on it.

These new products come as Up3 preorders begin shipping on April 20. It's been a long time coming - some customers ordered the Up3 band in advance around the holidays last year, and the release date was pushed back numerous times as Jawbone tried to fine tune the band's waterproof coating. In an effort to get the product in users' hands, the company announced the Up3 would ship this month as water-resistant, not fully waterproof.

The addition of NFC payments to the Up4 is a smart move by Jawbone - it makes it easier for users (American Express users at least) to go on a run without a wallet and pay for little things along the way. We're excited to get our hands on both the Up2 and the Up4 to test out the newest features and the mobile payments system.

Follow Valentina Palladino at @valentinalucia. Follow Tom's Guide at @tomsguide and on Facebook.