Stacey Salvi spent eight years at Fitbit — first as a lawyer, then in the product team, where she participated in the launch of nearly 20 devices for 116 million users. After that came the role of vice president of strategy at Movano Health and the development of the Evie smart ring for women. The logic of the next step turned out to be straightforward: if wearable devices have learned to count heartbeats and blood oxygen levels, why hasn't anyone yet measured the thing that determines the most common type of cancer in the United States.
What The90 Gem Does
A pendant necklace with built-in sensors detects UVA and UVB levels in real time and syncs with a mobile app. The app doesn't just show the UV index — it creates a personalized picture of accumulated "sun debt" and suggests when to reapply sunscreen. According to Engadget, the round pendant is available in gold and silver variants.
The launch price is $299, with limited early access at $199. According to Digital Trends, the device doesn't impose "AI in every line" — it simply gives you a number: how much UV you've already received today.
Why This Is More Than Just Another Self-Care Gadget
Context matters. 90% of melanoma cases — the most dangerous type of skin cancer — are caused by excessive exposure to solar and artificial UV radiation, and most of them could theoretically be prevented. In 2026, the American Cancer Society expects approximately 234,000 new melanoma diagnoses in the United States.
"UV is invisible, and people find it difficult to assess their actual exposure"
Frontiers in Medicine, study on non-melanoma skin cancer, 2024
This is where The90 comes in — the problem isn't just that people ignore sun protection, but that they lack feedback. Sunscreen applied in the morning doesn't account for spending three hours on a shaded terrace and then two hours on the beach. The pendant measures actual, not calculated exposure.
Is a Narrow Audience a Feature or a Limitation?
The90 openly positions the product for women — and it's not just marketing. According to research, women under 30 who use tanning beds have six times higher risk of melanoma. Meanwhile, men statistically less often use sunscreen and less often see a dermatologist. If The90 remains a niche "women's" product, half of the at-risk group will remain unaddressed.
Among the startup's investors is Lauren Boestalek, a well-known wellness influencer. This ensures distribution through a lifestyle audience, but at the same time complicates the perception of the product as a medical tool rather than a fashionable accessory.
If The90 manages to obtain clinical data showing that personalized UV monitoring actually changes user behavior — not just informs them — this could become an argument for insurance companies and dermatologists. Without this data, a $299 pendant will remain a beautiful answer to a real problem that most people still don't consider their own.
