Feature: 1. FEATURES: The sticker will turn from transparent to purple when it senses UV rays, the shade of the sticker color will change with the strength of the UV rays, when the color of the sticker is getting darker and darker, it suggests that you should make up for the sunscreen. 2. LATEX FREE ADHESIVE: Sunblock patches are made with a latex free adhesive to help kids ages 3 and up stay safe in the sun and help prevent sunburn. 3. REUSABLE: UV detection stickers are reusable and the color change lasts all day with each reapplication of sunscreen. 4. USES: Reusable UV detection stickers show you if you are applying enough sunscreen and when to reapply, which is perfect for outdoor use. 5. PLENTY OF QUANTITY: UV detection stickers are ideal for outdoor activities. Each pack contains 120 stickers, providing an ample supply for long term use. Specification: Item Type: UV Detection Stickers Material: PVC, Color changing paper Single Size: Approx. 1.5 x 1.5cm / 0.6 x 0.6in Quantity: 120 pieces Disposable: No, reusable. Package List: 120 x UV Detection Stickers Note: 1. The stickers are transparent in color when not exposed to UV rays, and they turn purple when exposed to UV rays. The stronger the UV rays, the darker the purple color of the stickers. 2. UV rays exist in both winter and summer.