The90 Gem Is the Smart Necklace Making UV Tracking Chic

The90 Gem wants to do for sun exposure what smartwatches did for the 10,000-step obsessed: turn an everyday habit into data you can actually see—and maybe nerd out over.

The debut device from preventative skin-health company The90 tracks real-time UVA and UVB exposure through a pendant necklace and companion app, giving you a personalized look at how much sun you’re actually getting throughout the day.

As a former beach lifeguard turned beauty editor, this launch struck a nerve. I still cringe when I think about the amount of UV exposure I racked up during eight-hour shifts in the sun, summer after summer, long before I understood that sun damage doesn’t only happen when you burn.

Unlike the UV Index on your weather app, which offers a broad, location-based estimate, the device measures your actual environment. Inside the app, there’s a Skin Monitor that shows your current burn risk and skin-aging risk, a Time to Burn countdown, UVA accumulation tracking and a Sun Exposure breakdown that separates protected and unprotected time. It also has a Vitamin D tracker that estimates how much more sun you need to reach your daily target, plus an “Own Your Light Index” that rewards sun-protection habits like following a sunscreen plan. Depending on your exposure, the app may prompt you to apply or reapply sunscreen or suggest post-sun skin-care steps, like reaching for an antioxidant serum at night.

The wearable itself is an unassuming pendant-style design, which makes it feel more like something you’d actually style than another device you have to remember to charge. And I’m certainly not the only one already paying attention: Lauryn Bosstick, founder of The Skinny Confidential, has invested in the company and is joining as an advisor, alongside strategic investors from the consumer tech, lifestyle and health spaces. The brand was founded by CEO Stacy Salvi, a wearable-tech veteran with experience at Fitbit and in the women’s smart-ring category.

The90 Gem is available now for $299 and comes in gold and silver.