Yes, it’s the blue dot on the person’s fingernail. Called UV Sense, the device is the first battery-free electronic UV sensor in the world, and it’s small enough to wear on one of your nails. Using NFC, the device can connect to your phone and deliver data on sun exposure.

Announced at CES 2018, the product will get a limited launch in the US ahead of the 2018 summer season, with a global launch to follow in 2019. That means you can’t get one in time for ski season this year. It also means we don’t have a price for the wearable at this time, but be prepared to buy a bunch of them when the sensor becomes available. You’ll want to share them with your family, and you might need to replace them from time to time.

The UV Sense is less than two millimeters thick and nine millimeters wide. It can be used for up to two weeks at a time, but you get additional adhesive in the box to extend its life. It may be small, but the gadget can store up to three months of data, which is quite impressive. Here’s what UV Sense looks like when torn apart:

L’Oreal says the wearable is powered by the mobile phone and activated by UVA and UVB rays. The mobile iPhone and Android apps will offer users data about UV exposure, which should help them either seek shade or reapply sunscreen.

The UV Sense is the evolution of the My UV Patch, a smarter device that can deliver real-time data to users.