The SARUNN ER Smart Ring puts health tracking in a form you can actually forget you’re wearing. It’s a minimalist alternative to a chunky wristband, designed for continuous, all-day insight without the bulk.

Its core function is passive monitoring. The ring tracks your heart rate and sleep patterns automatically, syncing data to your phone. You get a straightforward look at resting heart rate trends and sleep stages without needing to open an app. The included battery powers the ring for about a week, and the 0.1-inch OLED screen shows basic stats like time and step count at a glance. For activities like running or yoga, you can manually start a workout session for more focused tracking.

Getting the right fit is critical. You must measure your finger carefully using the provided chart; an improper fit will skew the heart rate data. The ring is water-resistant for handwashing, but it’s not built for swimming. Think of it as a comfortable, low-profile health monitor for daily life, not a dedicated sports device.