Personal Sun Intelligence
Get the good out of the sun. Own your light.
The sun has powerful health benefits, and it also carries real risk. The90 turns the light your skin actually gets into one daily Sun Score from 0 to 100, so you can balance and optimize your exposure. Aim for The90.
Built with world-renowned UV dermatologist Dr. Richard Weller.
One platform. Every answer you need.
The Gem sees it. The Score explains it. You own it.
The Gem
The modular UV sensor. Reads the real UVA + UVB hitting your skin and clips into the jewelry you already wear.
The App
UV exposure and skin protection is personal.
Your skin, your genetics, your day in the sun: no two people get the same UV, so a single Index number or a blanket SPF rule can’t tell you what’s actually reaching you. Up to 90% of visible skin aging comes from UV, and most of it happens when you aren’t paying attention. The Gem measures your real exposure and reads it against your skin, in real time.
A jewelry-grade sensor. A skin coach in your pocket.
Built to live in your jewelry stack and learn your skin.
01. Clip
Clip it into the pendant
The sensor measures UVA and UVB from every angle. Not from a zip code.
02. Measure
Measure your exposure
How close you are to a burn. How much aging exposure you’ve accumulated.
03. Optimize
Optimize your sun habits
Reapply, cover up, stay out longer. The Gem learns your skin over time.
Sun care that finally works like you do.
Personal to your skin
Calibrated to your type, genetics, and habits, not a generic UV index.
Tracks the rays that matter
Real-time UVA (aging) and UVB (burning), including the exposure that sneaks in indoors.
Protection and benefit
Enough sun for Vitamin D and circadian health, without the damage.
Wear it anywhere
Jewelry-grade, modular, and made for all-day life.
The90 Gem
Designed to be worn. Engineered to be used.
A precision UVA and UVB sensor disguised as a piece of fine jewelry. Pairs with the free app. Built for everyday life.
Reads UVA and UVB, separately
Reads UVA and UVB, separately. A photonic UV sensor captures the rays that matter, not just the generic UV index you get from your regional weather forecast.
Modular by design
Modular by design. The Gem is designed to be worn multiple ways. It clicks into the pendant and necklace today, with a hat clip, bag tag, and more on the way. You buy the sensor once, and it keeps finding new ways to be worn.
Built to actually be worn
Available in gold or silver, about the size of a nickel, with a concave face that shrugs off scratches. It layers with the jewelry you already own, so it never feels like a gadget.
Designed to go wherever you do.
The Gem blends into your everyday jewelry stack. Stack it, layer it, dress it up, sweat in it. The sensor doesn’t care. Your skin will.
Indoor
Outdoor
Active
Lounging
The90 Companion App
Your very own light dashboard.
See all your insights at a glance with The90 app. Think of it as a convenient hub for how your exposure is impacting your health.
The Sun Score
Your whole day in the sun, resolved into one number from 0 to 100, with a direction so you always know which way to tune tomorrow.
Skin Aging Zone
Know exactly what rays have hit your skin throughout the day, and what that means for your specific skin type. This way you can apply sunscreen or cover up before you burn, and get insights on what you can do to mitigate the aging effects of the sun.
We know now more than ever that the sun is vital to our health. With The90™ you can track these benefits like Vitamin D production, so you can maximize the benefits without risking damage from harmful UVA rays.
Built with leading skin and UV expertise.
We didn’t invent the science of UV. We built the wearable it deserves.
Dr. Richard Weller
World-renowned UV specialist. Chief Medical Officer.
Advisor 2
Add as confirmed.
Advisor 3
Add as confirmed.
What early adopters are saying
“I finally understand why my melasma flares in the car. The Gem caught UVA I never felt.”
Maya R. · Early access reviewer
“It looks like jewelry, not a gadget. My friends ask about the pendant before they ask about the tech.”
Sofia L. · Early access reviewer
“The reapply alerts alone are worth it. I burn less and I’m outside more than ever.”
Jenna K. · Early access reviewer
The Gem
Designed to be worn. Engineered to be used.
A precision UVA and UVB sensor disguised as a piece of fine jewelry. Pairs with the free app. Built for everyday life.
Tracks UVA (aging) & UVB (burning)
Personalized to your skin
Alerts when to reapply or shade
Free app, no subscription
$299
Free shipping · 30-day returns · 1-year warranty · No subscription
Own your light.
$299. Free shipping · 30-day returns · 1-year warranty · No subscription.
Is there a subscription or monthly fee?
No. Your Gem comes with the full The90 app and every core feature, with no monthly fee to read your own light. You buy the sensor once.
What does The Gem actually measure?
It reads the UVA and UVB reaching your skin, separately and in real time, then turns the day into a single Sun Score from 0 to 100. Along the way it tracks the light you want, like your morning circadian light and your estimated vitamin D, and the exposure you want to manage, like the UVA that ages your skin.
Do I have to wear it as a necklace?
It comes as a jewelry-grade pendant on a matching gold or silver chain, so you can wear it out of the box. The Gem is also a removable core, so it can move into new ways to wear it as they launch, including a hat clip and bag tag on the way.
How is this different from the UV Index or my weather app?
The UV Index gives one number for a whole city and says the same thing to everyone. The Gem measures the light actually hitting your skin, separates the aging rays from the higher-energy ones, and reads it against your personal skin profile in real time. It is the difference between a forecast and your actual day
Can I wear it in the water?
Rain, sweat, and a quick rinse are all fine. The Gem is water resistant to 1 meter for 30 minutes, so leave it off for the pool, the shower, hot tubs, and saunas.
What if it is not for me?
Try it for 30 days. If it is not right, send it back for a full refund, and every Gem is covered by a 1-year warranty. Free shipping, dispatched from California within 1 to 2 business days, currently within the US.
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