Another beneficial development to debut at CES, L’Oreal’s UV Sense tracks the sunlight exposure of its wearer. It’s a battery-free wearable that connects by NFC to an accompanying iOS or Android app. It’s also quite tiny: fit for a thumbnail, at 9mm in diameter and only 2mm thick. The reusable piece affixes to its user (or its user’s accessories) through an adhesive. For 2018, it will be available “exclusively through dermatologists,” according to CNET, but they mention “a global launch is expected in 2019.” The device is expected to sell for $40 or less.