Wearable fitness tracker brand Jawbone has just unveiled its newest designs for the UP2, UP3, and UP4 model bracelets.

The new options mean fitness-focused customers don’t have to worry about sacrificing style for function. Updated hardware, reliability, and functionality are also added bonuses of the new UP trackers.

Yves Béhar’s design studio paired with Jawbone to design the ultra-slim tracking bands made for 24/7 wear and data recording. Many of the new looks are so convincing that it’s difficult to decipher whether or not it’s actually a piece of fitness jewelry.

Users will also be happy to learn that the new Jawbone can automatically detect sleep, so wearers won’t have to tap their band to enter or exit sleep mode. Auto sleep tracking means more reliable sleep data so customers can continue to strive for a better night’s sleep.

Additional upgrades include passive heart rate tracking for the UP3 and UP4 models, which had only measured resting heart and sleeping rates.