The first UV WARNING STICKER with technology. The sticker imitates the texture of your skin and changes color from transparent to purple when you are no longer protected from the sun. A sticker lasts all day. It changes color several times — i.e. sunscreen can be applied more often during the day. - - - - How are the SaferSun UV warning stickers constructed? 1) The top layer with DermatRuetM technology absorbs sunscreen in the same way as human skin. 2) The detector layer: It is transparent when there is no UV light and turns purple when UV rays get through. 3) The adhesive layer: It is hypoallergenic and skin-friendly. The UV WARNING STICKER lasts all day and can also be worn during sports.