GoKawiilThe90's $249 Gem necklace tracks personal UV exposure in real time
The90 makes Gem, a $249 wearable necklace that monitors a user's real-time UV radiation exposure via a companion app and sends alerts when levels rise. A reviewer described using the device at an outdoor Los Angeles event, where it flagged rising UV exposure despite shade from a patio umbrella, prompting her to reassess her sun protection habits and investigate a medication-related heat sensitivity.