These are high quality Czech tempered glass, with the grit etched into the glass for a long-lasting file that can be washed and reused over and over again. The fine grit is powerful enough for shortening and reshaping nails, but not so harsh that it causes peeling or tearing. These crystal files are full-sized at 135 mm (5.3 inches) inches long and 2 mm thick. Nail file comes in a black velvet sleeve for protection.