Size: 15*10*1cm / 5.85"*3.90"*0.39" Package includes: 1pc UV detection sticker 1.Instructions for use: Place the sun protection sticker on clean, sweat-free, and hairless skin. If exposed to sunlight, the sticker will turn purple. Apply sunscreen and wait 5 minutes for it to absorb. Under the protection of sunscreen, the sticker will turn light purple or even transparent even if you are exposed to sunlight. 2.Reminder to reapply: If sun protection fails, the sun protection sticker will turn purple, indicating that it's time to reapply sunscreen. If the sticker's color does not lighten, it may be because you didn't apply enough sunscreen or the SPF is not high enough. Please choose a suitable sunscreen according to the intensity of the sunlight. 3.Waterproof UV stickers: We have enhanced the stickiness of these stickers, making them truly waterproof. Even if you wear UV stickers to swim, they will not fall off. The prerequisite is that you must apply them on clean skin. At the same time, we use low allergy adhesives that are suitable for children over 3 years old. 4.5 fun patterns: We designed 5 cute sticker patterns, including hearts, clouds, stars, moons, and flowers, for you to choose from. Children will be more willing to wear these UV stickers.can be placed on your arms, shoulders, and legs at the same time. Cute stickers make your outdoor activities more fun. 5.Note: UV detection stickers are designed as an auxiliary tool and should not replace the use of regular sunscreen. Always follow the correct sun protection guidelines and consult healthcare professionals for personalized advice.