Gain more insight into your health and lifestyle with the Oura Ring 4. This smart ring shows you how you sleep, how many steps you take, and when you're stressed. You can find this information in the Oura app. You also find tips to improve your lifestyle there. A breathing exercise for when you're stressed, for example. Order a sizing kit before you order an Oura Ring 4. That way, you're sure you buy the right size. You receive the purchase price of the sizing kit as CoolblueCredit in your account. You can use this credit when you buy an Oura Ring 4 at Coolblue.