SHAPE: Start with the medium-grit inner curve to adjust nail length and shape. Hold file at a slight angle to nail and file in one direction to help prevent nails from splitting and peeling. Work from the sides of each nail to its center. Careful! Don’t file too deeply into nail sides or they may weaken. SMOOTH: Use the fine-grit outer curve for a perfectly smooth finish. The innovative convex design won’t nick fingertips as you file. CARE: Please keep clean for good hygiene — rinse with soapy water after use and pat dry.