Battery days, sensor duty cycle and accuracy conditions — three lines that tell you more than the marketing page.
When a ring claims seven days of battery, ask what the sensor duty cycle is overnight — that is when most of the measurement happens.
When accuracy is quoted, ask under which conditions: resting or moving, which wrist temperature, which skin tone range. A number without conditions is a marketing claim, not a specification.
We publish all three for our own products, and we are happy when partners hold us to them.
