Smooth-flowing ink delivers scratch-free writing every time. Vibrant gel water-based ink is acid-free and archival quality, keeping your documents clean and secure. See-through barrel lets you know when you're running low on ink. Buy 20 black, get two blue and two red free. Special Ink Type: Gel; Pen Style: Retractable; Ink Color(s): Black; Pen Type: Roller Ball.