The patented airplane-safe technology prevents leakage on flights. Features Uni-Super Ink&trade that helps prevent against check and document fraud. Fade-proof acid-free waterproof ink provides permanence for important documents. Transparent barrel window shows when you're running low on ink. Special Ink Type: Water-Proof Pen Style: Stick Ink Color(s): Blue Pen Type: Roller Ball.Unit of Measure : Each