I can't believe the bad reviews about poor customer service - Oura has provided me with some of the best customer service I've ever experienced! The kindness and compassion they showed me has been above and beyond. I purchased my Ring 4 in December and after a very serious health issue I lost a lot of weight and my ring was unwearable because it fell off all the time. I couldn't afford to replace it and as it was 6 months old I was out of any return window. I also bought it from John Lewis and not Oura directly. However they made an exception and accepted my ring back to exchange for a smaller size. They provided the return postage label too. Oura also gave me 3 months complimentary subscription. Shout out to Lucy, Emily and Matt who provided amazing, compassionate customer service. The Ring 4 is an amazing product. It's health tracking is so accurate and the battery lasts several days. It accurately helped me track my health metrics when I was sick which provided a lot of comfort.