Wearable UV Sensor for Skin Health

Get the good out of the sun. Own your light.

Checking UVI on your phone gives you an idea of the weather, but it doesn’t tell you what you’ve actually been exposed to. The90™ Gem tracks both UVA & UVB exposure in real time and provides insights along the way.

"I Don't Put My Name On Anything I Don't Fully Believe In."

“I Don’t Put My Name On Anything I Don’t Fully Believe In.”

✦ Lauryn Bosstick, The90 Investor and Creator of the Skinny Confidential.

The90 turns the light your skin actually gets, the vitamin D and morning light you want and the aging and burning you don't, into one daily Sun Score from 0 to 100. Aim for The90.

The90 is a personal sun intelligence system. A jewelry-grade sensor and a connected app measure the Personal UV your skin actually gets, then turn it into one number you can act on.

Sunlight gives. Sunlight takes. The difference is knowing your dose.

The UV Index tells you what may be happening outside. The Gem shows what is happening to you.

Stop guessing. Start understanding your light.

Sunlight is essential.

It helps support vitamin D production, regulates your circadian rhythm, and connects your body to the natural day.

But the same light can also burn your skin and accumulate as long-term UVA exposure.

Sunlight is essential.

It helps support vitamin D production, regulates your circadian rhythm, and connects your body to the natural day.

But the same light can also burn your skin and accumulate as long-term UVA exposure.

Personalized to your skin recommendations based on your unique skin profile, genetics, habits, and sensitivities.

Tracks the rays that matter. Measure both UVA (aging) and UVB (burning) in real time – including the exposure that quietly adds up through windows, cars, errands, and more.

Built for everyday life. Wear it with your existing jewelry, pair the Gem with The90 app, and get guidance on when it's time to reapply, cover up, or get out of the sun.

One Platform. Every answer you need. The Gem sees it. The Score explains it. You own it.

The jewelry-inspired UV sensor that tracks what your skin actually experiences, so you can protect how you age while harnessing the health benefits of the sun.

Finishes

Track what silently adds up

Monitor UVA exposure (rays linked to premature photoaging and long-term skin damage) even when you can't feel or see it.

Water Resistance

Track what silently adds up

Monitor UVA exposure (rays linked to premature photoaging and long-term skin damage) even when you can't feel or see it.

Accessories

Track what silently adds up

The90 Gem was designed as a timeless piece of jewelry women actually want to wear. Elegant, customizable, and made to fit every moment.

Jewelry Design

Track what silently adds up

Monitor UVA exposure (rays linked to premature photoaging and long-term skin damage) even when you can't feel or see it.

Advanced Sensors

The jewelry-inspired UV sensor that tracks what your skin actually experiences, so you can protect how you age while harnessing the health benefits of the sun.

Finishes

Track what silently adds up

The90 Gem was designed as a timeless piece of jewelry women actually want to wear. Elegant, customizable, and made to fit every moment.

Jewelry Design

Track what silently adds up

Monitor UVA exposure (rays linked to premature photoaging and long-term skin damage) even when you can't feel or see it.

Water Resistance

Track what silently adds up

Monitor UVA exposure (rays linked to premature photoaging and long-term skin damage) even when you can't feel or see it.

Advanced Sensors

Track what silently adds up

Monitor UVA exposure (rays linked to premature photoaging and long-term skin damage) even when you can't feel or see it.

Accessories

Stop guessing what your skin needs. The90 shows your UV exposure in real time, and tells you what to do about it.

Know your sunburn window

See your estimated time to burn based on real-time UVB exposure (rays that cause sunburn), sunscreen use, and skin profile.

Track what silently adds up

Monitor UVA exposure (rays linked to premature photoaging and long-term skin damage) even when you can't feel or see it.

Build smarter sun habits

See your daily sun exposure patterns, track how your habits add up, and get personalized recommendations on how to protect your skin over time.

Tracks the rays that matter. Measure both UVA (aging) and UVB (burning) in real time – including the exposure that quietly adds up through windows, cars, errands, and more.

Stop guessing your UV exposure.

Own your light

Order Now

Limited units available, pricing only available while supplies last

Meet The Gem

The jewelry-inspired UV sensor that tracks what your skin actually experiences, so you can protect how you age while harnessing the health benefits of the sun.

Meet The Gem

The jewelry-inspired UV sensor that tracks what your skin actually experiences, so you can protect how you age while harnessing the health benefits of the sun.

See What Your Skin Feels

Checking UVI on your phone gives you an idea of the weather, but it doesn’t tell you what you’ve actually been exposed to. The90™ Gem tracks both UVA & UVB exposure in real time and provides insights along the way.

Create your skin profile

The90™ app walks you through a series of questions that help us build your specific skin profile. Genetics, habits, and sensitivities all play a role in how your skin reacts to the sun.

Track UVA & UVB

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.

Harness the benefits

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.

Create your skin profile
The90™ app walks you through a series of questions that help us build your specific skin profile. Genetics, habits, and sensitivities all play a role in how your skin reacts to the sun.
Create your skin profile
The90™ app walks you through a series of questions that help us build your specific skin profile. Genetics, habits, and sensitivities all play a role in how your skin reacts to the sun.
Create your skin profile
The90™ app walks you through a series of questions that help us build your specific skin profile. Genetics, habits, and sensitivities all play a role in how your skin reacts to the sun.

Designed to Go Wherever You Do

Made to look as good as it performs, The90™ Gem blends seamlessly into your everyday jewelry stack, so you can wear it from workdays to workouts to weekends in the sun and everything in between.

Indoor

Indoor

Outdoor

Outdoor

Active

Active

Lounging

Lounging

Built With Leading Skin and UV Expert

Dr. Richard Weller

World Renowned UV Specialist & Dermatologist

Chief Medical Officer

The Gem

Personal UV Sensor + App

$199

$299

Order Now

The Gem

Personal UV Sensor

$199

$299

Order Now

Frequently asked questions.

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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2026

Own your light