Oura Ring Gen 4 size 10 charging dock with USB-C cable. Includes box. OURA RING 4 CHARGER - This is the only way to charge your Oura Ring 4. This USB-C cable charger is size specific, so be sure to get the size that fits your Oura Ring 4. You can find your Oura Ring 4 size on the inside of your Oura Ring 4. • CHARGERS ARE SIZE-SPECIFIC - Your Oura Ring 4 size can be found on the inside of your smart ring. • CHARGING TIME - Your Oura Ring 4 typically charges fully in 20-80 minutes, depending on its current battery level. • BATTERY LEVEL IN OURA APP - You can check the battery level by tapping the circular icon in the upper right-hand corner of the home tab. • POWER CORD COMPLIANCE - The USB-C to USB-C Oura Ring 4 Cable cord is intended to be supplied by an external 5Vdc supply that complies with IEC 62368-1 standard.