Sheet masks are a popular beauty care product, typically made of thin cotton or fiber fabric. They are soaked in a serum containing ingredients that are beneficial for the skin, such as vitamins, minerals, and extracts. Sheet masks are designed to fit the contours of the face and are left on for a period of time, usually 15-30 minutes. When removed, the skin is left feeling softer, smoother, and more hydrated. Sheet masks can be used to treat a variety of skin issues, including dryness, dullness, and wrinkles.