Each style has identical technical and hardware capabilities. Water resistant up to 100 m (more than 328 ft.) Lighter than a conventional ring (4 to 6 grams) Titanium: durable and wearable Includes size-specific charger and USB-C cable With daily wear, the ring may develop scratches Ring sensors should be on the palm side of your finger for the most accurate reading. To help ensure optimal positioning. Oura Heritage has a classic, plateau design with a flat surface on top. Membership is $5.99/mo. Sleep, Readiness & Activity scores are just the beginning. Members also get: In-depth sleep analysis every morning Personalized health insights & recommendations Live & accurate heart rate monitoring Temperature trend monitoring as a tool to predict periods and to identify early signs of sickness.