Instructions for use; 1. This product is purely imported and does not fade even at temperatures below 50 degrees. 2. This product disappears immediately when the fabric temperature reaches above 60 degrees. Due to the different chemical composition and logistics properties of different materials, some materials may leave traces after disappearing. Please make sure to conduct a small test before putting it into production. If the effect is not satisfactory, please stop using it. If you put it into production without testing, the consequences will be at your own risk.Our store does not bear any responsibility. After use, promptly cap the pen and store it in a cool place away from direct sunlight. This product is intended for industrial production marking only and should not be used for writing contracts or signing important documents.