What does the passage focus on?

Over 75, 000 new cases of melanoma will be diagnosed this year in the U. S. , predicts the American Cancer Society, and many of those incidents are directly due to the high summer sun. The risk isn’t just in the hunt for the perfect golden tan — it’s also in the ultraviolet radiation we are exposed to throughout the summer months even when we’re not at the beach. UV light is incredibly deceptive; even a cloudy day can deliver potentially cancerous rays.
   A new wearable device accurately tracks your daily UV exposure, protecting you from the sun without messing up your beach day outfit. The My UV Patch sticks to your skin like a temporary tattoo, stays on after a swim or shower and is so thin — just 150 microns thick, thinner than a human hair — that it wrinkles like your own skin, making it less obtrusive than any other UV- reading wristband or patch on the market, according to manufacturer L’Oreal.
   The tech behind the wearable is remarkably simple: It has photosensitive blue squares that change hue when exposed to sunlight. You snap a photo with your phone, and an app reads the changes in the image. You put the patch anywhere you worry about getting too much sun, like the back of the neck or hand, and it’ll last for days.