LIFETIME GUARANTEE - Effective filing surface allows for precision shaping. Each nail file comes with a lifetime guarantee which covers the filing surface. All glass nail files we sell are chemically hardened which greatly increases their mechanical resistance. PREMIUM QUALITY - Crystal glass nail file is dual sided and made of premium quality Czech crystal glass. The grit board is permanently chemically etched (acid engraving) on both sides of the glass, so it will not degrade over time and will last a lifetime. TAKE IT ANYWHERE - Use it when and where you want. Use it in a bath or in a chair, at home or while travelling. No batteries or spares - just wash it, dry with a towel and use it again. Protective plastic case included, easy to store or bring with you on the go. GOOD HEALTH OF YOUR NAILS - Won't chip, tear or split nails. Gentle surface allows your nail care to be easy, smooth and most importantly safe, without damaging your nails. Better than emery boards and paper nail files. Professional manicure and pedicure without extra costs. DIFFERENT GRITS - Contains 3mm thick medium nail file with two different grit surfaces in protective case. Different grit surfaces allow use this nail file for fast filing and finishing nails.