The device, My Skin Track/UV, has been developed in partnership L'Oreal's skincare brand La Roche-Posay and Professor John Rogers from Northwestern University -- the same guy that introduced wearable tattoos back in 2016. Powered by the user's smartphone using near-field communication, the sensor is activated by the sun and provides instant status updates while storing up to three months of data. Its primary function is UV monitoring, but integration with Apple HealthKit means it also provides insight into humidity, pollen and pollution. And it's waterproof.

"La Roche‑Posay believes that better looking skin starts with healthy habits. That's why we are committed to bringing scientific progress directly to consumers, so that they can make well‑informed decisions that will help them take exceptional care of their skin," said Laetitia Toupet, global general manager of La Roche‑Posay. Indeed, L'Oreal's research indicates that its previous UV monitoring technology lead to a direct increase in sun-safe behaviors, such as seeking shade and applying sunscreen more frequently. The device is available from apple.com and Apple stores in the US for $60.