Everyone knows what happens when you’ve been out in the sun for too long; you get burned. Which then causes days of pain and many times of reapplying aloe. Those days might be over however with wrist bands that warn the user of too much sun exposure.

Australian researchers have found that invisible ink darkens when exposed to long amounts of ultraviolet light (UV). The ink will be written on a piece of paper that could be made into a bracelet which will be worn to warn the wearer of too much sun. The chemical the ink is made of, polyoxometalate, turns darker blue when exposed to UV light. When exposed to UVB light, the worst kind of UV light, the bands will turn blue much faster than when exposed to UVA light.

Sunlight helps the skin gain Vitamin D levels but no one is able to tell when they have had enough. “People fail to understand that UV light is not hot. The amount of sun that you feel has nothing to do with the intensity of the sun or the heat of the sun,” Bansal, a chemistry professor at the University of Melbourne in Australia, said. Skin Cancer is the most common type of cancer and with the bracelets, skin cancer totals hope to be reduced.