The Gem: a UV-sensing pendant that personalizes sun exposure guidance
The90 unveils The Gem, a pendant necklace with UVA/UVB sensors that feeds real-time sun exposure data to a companion app, building a personalized skin profile and delivering actionable guidance—from UV thresholds to sunscreen reminders and optimal exposure windows. Created by former Fitbit executive Stacy Salvi, the device is available now for $300, with a limited-time $200 early-bird price.