The Uni-ball Vision Elite Stick Roller Ball Pen\ s ink will not explode or leak due to a change in cabin pressure during flights. The exclusive uni-flow ink system regulates a steady flow of waterproof ink to the point for consistent smoothness and color intensity down to the last drop of ink. The Uni-ball Vision Elite Stick Roller Ball Pens feature Super Ink that is specially formulated to become trapped in paper helping prevent criminal check washing and other document alteration.