Oura

Oura makes a smart ring that tracks health data. Petteri Lahtela, Kari Kivela and Markku Koskela founded the company in 2013 in Oulu, Finland. It has offices in Finland and the United States.

The Oura Ring measures heart rate, heart rate variability, body temperature, blood oxygen and movement from the finger. The companion app gives daily scores for sleep, readiness and activity. It also offers period and fertility tracking, stress tracking and other features. Most features need a monthly membership on top of the ring purchase.

Oura sells the ring through its own website and through large retailers. It also works with businesses, sports teams and research groups that use the ring to study sleep and health. The company has bought several smaller health software firms to add features. Each new ring generation has been smaller and has added sensors. Tom Hale is chief executive. Oura has raised several funding rounds and remains privately held.