Oura's fifth smart ring is 40% smaller than its predecessor, and at $399, it still commands a premium.
Oura released the Ring 5, calling it the world's smallest smart ring. The shrink is real: 40% smaller than the previous model means a noticeably slimmer profile on your finger. The device starts at $399. Whether the hardware justifies that number depends on what sensors and software Oura packed into the space it reclaimed.
Size matters in smart rings more than in almost any other wearable category. People abandon rings that are uncomfortable, and the category's edge over smartwatches is exactly that you forget you're wearing it. Oura now faces Samsung's Galaxy Ring, which means "world's smallest" is doing real marketing work: the company needs hardware reasons to hold its price premium over a well-resourced rival.
"World's smallest smart ring" sounds definitive and says nothing about whether the health tracking is actually accurate.