I took apart the Oura Ring - both gen 3 and gen 2 devices.
Oura Ring Gen3 Review: A Stylish, Intuitive Sleep Tracker
Furby 2023 Teardown
Oura Ring Teardown (Gen 3 and Gen 2) - Becky Stern
Oura Ring Gen 3 Review 2022: A Smart Ring With Valuable Health
Oura Ring review: love the feature changes, hate the new
Oura ring gen3 取扱店は - アクセサリー
Oura Ring Review: Is the generation 3 model worth the money?
Oura 3 vs Circular Ring — paper-based comparison
Oura Ring Generation 2 - その他