The UV-tracking Gem made me rethink how sunlight affects my health, not just my appearance.

Half an hour later, I felt exhausted, dizzy, nauseous, and generally unwell, symptoms consistent with heat exhaustion. .
Around the same time, I received a notification from an app used by the $249 ($149 at the time of publication) UV-tracking necklace I’d been wearing, called Gem, from a company called The90. With temperatures rising to the 90s in Los Angeles, avoiding the heat wasn’t exactly an option while I was at a relative’s outdoor party in August. It warned that my UV exposure had climbed considerably.