If you purchase La Roche-Posay sunscreen this summer, it may come with a complimentary device that looks something like a heart-shaped Band-Aid. But it’s even thinner—half the width of a human hair—and unlike a Band-Aid, it contains miniature electronics that connect to your smartphone and monitor your sun exposure in real time.
Launching in June from La Roche-Posay parent company L’Oréal, My UV Patch is the first stretchable electronic for mainstream consumers. Stick it anywhere on your skin, wear it for up to five days, and use the accompanying app to see how many rays you’ve soaked up. If it sounds simple, it isn’t: the tiny device contains a near-field communication (NFC) antenna and a microchip, which wirelessly send signals to your phone, as well as photosensitive dyes that change color based on their exposure to light.