Ring 4 - Rose Gold - Size 8

It seems to me that creating a rechargeable Index ring is way more feasible than creating one that where the battery can be replaced. You’d likely destroy it trying to change the battery. Having compared the Index sizing kit ring against my Oura Gen 4 ring, the Index is only a tiny bit smaller (a li

Oura ring is for sure the best reliable option so far in my opinion , expensive but delivers with Gen 5 being so slim and comfortable, if you can't afford get a Gen 3 or 4 that have great discounts these days and do the same , it has a subscription but now even added blood pressure insights and all

Devices in the image (left to right, top to bottom): Whoop band (black strap with gold clasp): Subscription-focused recovery/fitness tracker. No screen, emphasizes strain, recovery, and sleep via app. Battery 4-5 days. Strong on HRV and workout strain scoring. Requires membership ($199+/yr). Oura