High-quality ball pens must provide a smooth, skip-free writing experience. When sourcing, prioritize ink that is quick-drying and smudge-proof to prevent staining, especially for left-handed users. For professional or archival use, ensure the ink is document-proof (ISO 12757-2 standard), meaning it is resistant to water, light, and chemicals. The ball tip should be made of tungsten carbide to ensure durability and consistent ink flow over a long writing distance, typically measured in meters (e.g., minimum 1,000 to 2,000 meters for premium models).