RingConn is a Chinese wearable company that makes screenless smart rings for sleep, activity, stress and recovery tracking. The ring is worn on a finger day and night, with results in an app without a required subscription.

How it works
Green and red lights measure changes in blood flow and oxygen at the finger. Temperature sensors track skin, while motion sensors record movement and activity. Software combines these signals to estimate heart rate, breathing, sleep timing and stages. Selected models also look for oxygen drops linked with sleep apnea risk.

Key considerations
A close fit is necessary, and cold hands, movement or loose contact can create gaps. Sleep stages and recovery scores are algorithmic estimates. Sleep apnea monitoring is unavailable on some models and cannot confirm a diagnosis. RingConn avoids a membership fee, though the ring still requires regular charging and eventual hardware replacement.