Oura Ring 4 Ceramic Midnight Size 4

Description

Oura Ring 4 Ceramic in Midnight is a health-tracking smart ring in Oura size 4, manufacturer code JZ90-57455-04. Its premium zirconia ceramic exterior surrounds a seamless titanium interior designed for comfortable 24/7 wear. Smart Sensing adapts to the finger and supports sleep, readiness, activity, stress, heart-rate, HRV, blood-oxygen, respiratory-rate and temperature-trend insights in the Oura app.

The ring is water-resistant to 100 m and connects to compatible iOS and Android phones using Bluetooth Low Energy. Battery life is rated at 5–8 days, with a full charge taking approximately 20–80 minutes. The size-specific charger uses the supplied USB-C cable; a wall power adapter is not included.

Package: Oura Ring 4 Ceramic Midnight size 4, size-specific charging dock, USB-C cable, ceramic polishing pad and documentation. Oura sizes differ from standard ring sizes, so use the official sizing kit before purchase. Full app functionality requires an Oura Membership after the included trial period; membership terms vary by region.