NEW YORK (CBS) – Want to know when you’re getting too much sun? A new high-tech patch may be able to help.

The “My UV Patch” has photo-sensitive dyes that change color when exposed to ultraviolet rays.

sun patch High Tech Patch Changes Color Before You Get Too Much Sun

The My UV Patch (Image credit: CBS News)

Wearers then use a smartphone app to scan it and find out if it’s time to put on more sunscreen.

“This is a way to tell them when to re-apply, that there is sun damage that is going on, even if you don’t see it,” dermatologist Dr. Gene Rubinstein tells CBS News.

The patch can be worn for up to three days at a time, even while swimming.

L’Oreal’s La Roche-Posay introduced the patch last year and it’s free with sunscreen purchased on the company’s website.

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