Can a paper wristband will help sunbathers avoid sunburn? The idea comes from a team at Strathclyde University in Scotland, who say that the band will let you know when its time to slap on some sunscreen by indicating the level of UV exposure.

Commercialisation Manager with Strathclyde Univsersity’s Research and Knowledge Exchange Services Fiona Strang explains more about the technology to the Daily Mail:
The sunburn monitor will make a significant contribution to public health as an affordable, fashionable device which enables people to enjoy the benefits of the sun while at the same time keeping them alert to the risks of over- exposure.
The band is coated with a acid-release agent that can pick up UV light. Once the pH levels in the indicator reach a certain limit, the band will change color from yellow to pink. They've also adapted the wristbands to change color faster for fairer skin wearers to reflect the different tolerance levels that they have to the sun.