What is it: A set of two crystal nail files with unique patented surfaces that easily shape and file. They create a smooth edge on the nail. Who is it for: All nail types, natural or artificial. Why is it different: Its unique patented filing surface is gentle enough to use on weak nails and abrasive enough to use on acrylic nails. How do I use it: File nails in any direction. Use on polished or unpolished nails. From Perfect Formula. Includes: