Luna is an Indian wearable technology brand offering a smart ring and health band. Its devices track sleep, activity, stress and recovery, while the LifeOS app connects body signals with logged habits. No subscription is required.

How it works
Optical sensors use light at the finger or wrist to estimate heart rate, heart rate variability and oxygen. Temperature sensors follow skin trends, while motion sensors detect activity and sleep. Software combines these signals into sleep, readiness, stress and circadian insights. Users can add context through the app and keep one history for Luna devices.

Key considerations
Features differ between the Ring and Band, and availability varies by market. Fit, motion, cold skin and charging gaps can affect measurements. Sleep stages, stress and readiness are calculated estimates, and fertility features do not provide contraception.