Rollerball Pen One Hybrid C 03. Ink type: water-based ink, indelible. Refill design: Hybrid cone tip for comfortable soft writing, 0.3 mm, assorted. Can be left open for a few days without drying out. Ink storage technology: Free Ink System Pen design: plastic, ergonomically rubberised. Clip material: High quality metal clip. Super flow system for smooth ink flow. Large ink supply with viewing window. Barrel colour: denim blue. Box contents: pack of 4 cases (black, red, blue, green).