Please note: As sizing differs from standard ring sizes, we would recommend first purchasing the Oura 4 Sizing Kit to find your perfect fit. You will then receive a £10 credit, which can be used towards the purchase of your Oura Ring. Need to know1. Purchase the Oura 4 Sizing Kit2. Wear the sizer for 24 hours to find your best fit3. Purchase your Oura Ring 44. New Oura members get one month free subscription. Then its £5.99 a month. Oura Ring 4 Ceramic is a modern expression of our revolutionary smart ring technology that blends refined elegance with everyday comfort. The high-performance ceramic exterior is designed to keep up with you and all that you do. The Ceramic Collection is available in four unique colors: Midnight, Petal, Tide and Cloud. Each new color is built to accent your style and personality. Key Features:. | Oura Ring 4 Ceramic Petal, Size 8