I took apart the Oura Ring - both gen 3 and gen 2 devices.
Oura Ring Generation 3 In-Depth Review
Oura Ring 3 v Circul+: Battle of the smart rings - Wareable
Oura ring gen3 取扱店は - アクセサリー
Oura Ring 2 Teardown - iFixit
The Oura Ring Is a $300 Sleep Tracker That Provides Tons of Data
Oura Ring Teardown (Gen 3 and 2)
Oura Ring Teardown (Gen 3 and 2)
Oura Ring Generation 3 In-Depth Review
Oura's gen-3 fitness ring arrives with improved sensors, custom
最短翌日到着 oura ring Gen2 - アクセサリー