Most of us know that applying sunscreen is important – we’ve heard it time and time again. Still, on a day-to-day basis, we often rely on our instincts, habits, weather apps, or a generic UV index that doesn’t necessarily say much about what your skin is actually experiencing. The90 Gem is trying to make that exposure a little more personal. It's a sleek, necklace-style tracker that transforms invisible sun exposure into actionable, app-based skincare guidance.
The pendant pairs with The90 app, which processes live UVA and UVB data throughout the day. Rather than simply warning you that the sun is strong, it translates that ambient exposure into proactive skin-care management. Despite essentially being a health tracker for the sun, the Gem feels more like a beauty-focused wellness accessory built around prevention.
While standard weather apps only offer broad, location-based estimates, the Gem measures the precise, real-time UV levels surrounding the wearer. This captures cumulative exposure that traditional metrics miss: light coming through windows, time spent in the car, outdoor workouts, or brief walks between meetings.
The app also separates UVA and UVB exposure. UVA is tied more to long-term skin aging, while UVB is the bigger sunburn concern. It then combines sensor data with the wearer’s skin profile, sunscreen use, protective clothing, and sun habits to create practical guidance. These include an estimate of how long until your skin burns, your daily UVA and UVB accumulation, when you should reapply sunscreen, and personalized thresholds.
The design is just as important as the sensor. The90 Gem isn’t just another wristband or clip-on sensor; it’s a pendant necklace made to sit alongside other jewelry, available in Gold and Silver variants. The images on its website make this point clearly: it’s meant for workdays, workouts, weekends, and lounging. This matters because UV tracking only works if people actually keep the sensor on them.
The90 is framing the Gem around a familiar idea: much of visible skin aging is linked to cumulative UV exposure, not just the obvious beach days or long afternoons in direct sun. The idea is to shift sunscreen from a once-in-the-morning habit into something more informed and responsive – adjusting reminders and guidance around actual exposure, skin profile, and daily behavior.
There’s a clear beauty and wellness angle here, too. Investor and advisor Lauryn Bosstick, founder of The Skinny Confidential, brings along a built-in audience in the skincare community. Meanwhile, The90’s founder, Stacy Salvi, brings wearable-tech experience. Still, the Gem is meant to be a behavior-guidance tool, not a replacement for a dermatologist or a guarantee against sun damage.
The device also reflects a shift in wearables, moving beyond broad health metrics like steps, sleep, and workouts, toward more specific preventive tools. Skin health makes sense here: UV exposure is constant, invisible, and highly personal.
Both the Gold and Silver variants of The90 Gem are available now on The90’s website. The list price is US$299, but a launch promotion drops either color variant to $199 when using the auto-applied promo code "THEBOSSTICKS."
Product page: The90 Gem
