Smart ring Colmi R03 18.9 mm size 9 Black — wearable health & notification device

Colmi R03 smart ring in black (inner diameter 18.9 mm, size 9) is a compact wearable that provides on-finger monitoring of basic health metrics and records physical activity. The ring is made of a titanium alloy, weighs 4.7 g and is rated 5ATM for water resistance. It connects via Bluetooth 5.0 to the QRing app (Android, iOS, Harmony OS) for viewing daily, weekly and monthly reports and managing settings. The set includes the smartring, a magnetic charging case with USB-C, a USB-C cable and a user manual.

Advantages

The Colmi R03 combines lightweight titanium alloy construction with 5ATM water resistance and long battery support via a portable charging case. It measures heart rate, blood oxygen saturation and sleep phases, records steps, calories and distance, and supports 21 sports modes. The ring charges in about 1 hour, offers 3–5 days of standalone operation and the included case can recharge the ring multiple times from its 200 mAh battery.

Suitable for

• Everyday health monitoring (sleep, heart rate, SpO2)
• Activity tracking and workout logging
• Swimming and water-based exercise (5ATM)
• Users who prefer discreet wearable form factor

Key specifications

• Manufacturer: Colmi
• Model: R03
• Color: Black
• Size / Inner diameter: 9 / 18.9 mm
• Material: Titanium alloy
• Weight: 4.7 g
• Main chipset: BlueX Micro RF03
• Memory: ROM 512 KB
• HR sensor: Vcare VC30F
• Accelerometer: STK8321
• Bluetooth: 5.0
• Ring battery: Li‑Po 15 mAh, magnetic charging, ~1 h charge time, 3–5 days operating time
• Charging case battery: Li‑Po 200 mAh, USB‑C charging, recharges ring up to 13 times, ~1 h case charge time
• Number of charging cycles (ring/case): over 300 / approximately 300
• Water resistance: 5ATM
• Compatibility: Android 4.4+; iOS 8.0+; Harmony OS
• App: QRing
• Available app features: step counter, calories, distance, heart rate, sleep monitoring, 21 sports modes, exercise log, blood pressure, SpO2, stress level, remote photo
• Updates: OTA

How to use

Install the QRing app on a compatible Android or iOS device and pair the Colmi R03 via Bluetooth 5.0. Wear the ring on a finger that provides a comfortable and stable fit, ensuring the sensors maintain contact with the skin. Use the app to view real-time measurements, configure sport modes and access daily, weekly and monthly health reports. When the ring battery is low, place it in the magnetic charging case and plug the case into power via the included USB‑C cable.

Recommendations

For the most accurate heart rate, SpO2 and sleep readings, wear the ring snugly but comfortably and keep the sensor area clean. Avoid exposing the ring to strong chemicals or abrasive surfaces; although it is 5ATM water resistant, avoid prolonged exposure to hot water and high-pressure jets. Charge the case and ring regularly to maintain continuous monitoring and install app updates (OTA) when available.