The Trind Professional Glass File is made of durable glass, making this file a professional instrument of the highest possible quality.The Trind Professional Glass File lasts a lifetime and is easy to use. Filing and shaping nails instead of cutting them, helps prevent dirt from entering the nail and leaves your nails sealed and smooth.Directions for usePlace the Trind Professional Glass File to the edge of the nail and then move it with light pressure from the outside to the middle of the nail. This way of filing prevents dirt from entering the nail. We advise you to never cut the nails. For hygienic reasons, clean the Trind Professional Glass File with hand warm water after use. If the file is damaged or broken, discontinue use.