Glass Ball UV Detection Cell Phone Strap
This set of beautiful looking cellphone charms not only look good hanging off your cell phone, but come with a secondary purpose as UV detection devices. They are made to contain a special property that makes them change colors when UV rays are detected.
The sakura/pink version for example turns a hue of purple as it absorbs UV radiation and the color gets stronger as the amount of radiation increases. Definitely good for those who are conscious about the amount of UV rays their skin absorb during the day. There are six designs to choose from and each goes for 420 yen, buy from Strapya-World.