The Leighton Denny Crystal Nail File is a high-quality nail file made of crystal that is designed for use on natural nails only. It is not suitable for use on gel or acrylic nail enhancements. The file is designed to be used by filing back and forth, making it quick and easy to use. The unique surface of the file glides along the nail edge, turning the nail to dust and sealing the nail edge to help prevent splitting and peeling at the tips. The file comes with a storage case and includes a 25-year guarantee for the file surface never to go dull. However, due to the nature of the material, the guarantee does not cover breakage no matter how caused. The Leighton Denny Crystal Nail File is available in different sizes, including a small size of 135mm and a large size of 195mm. The product is made of crystal, but the ingredients or materials used to make it are not specified in the search results.