Celebrities, CEOs , and health optimizers, including Mark Zuckerberg, Jennifer Aniston, Kim Kardashian, and Gwyneth Paltrow, have been seen sporting the Oura ring . The wearable has become a wellness staple (more than 2.5 million rings have been sold), as a growing number of people have started tracking their biomarkers, especially their sleep, to optimize their overall health.

Today, wearable fanatics are in luck because the Oura ring just got a significant upgrade to improve accuracy, battery life, and comfort. ŌURA, founded in 2013 in Finland, announced Thursday the launch of Oura Ring 4. The $349 updated version utilizes sensing technology for more accurate health readings, according to the company.

The new model has 18 sensory pathways compared to the current model’s eight, so it shouldn’t matter if the ring is out of alignment on the finger to get accurate readings, Jason Russell, ŌURA’s vice president of product, tells Fortune . The lack of protruding domes in the ring’s interior is the most evident design change, which should increase comfort, Russell adds. The app’s platform has also been redesigned to streamline data in three core sections: Today, Vitals, and My Health.

How did the Oura ring change? The device, worn on the pointer finger, tracks your quantity and quality of sleep, stress levels, and overall readiness for the day by measurements like heart rate variability and activity—and it’s been increasingly purchased by Gen Zers and millennial .