Uni-Ball Vision Elite Bold No. 67180 Pack of 4 Pens - Bold Point - 0.8mm Enjoy smooth writing performance right down to the last drop of ink, thanks to the advanced liquid ink UNI-FLOW SYSTEM. Ink that is waterproof, resistant to fading and discolouration from exposure to light and possesses superior colour brightness. TIP Stainless steel BALL 0.8mm dia. tungsten carbide ball Airplane Safe Technology - prevents leakage on airplane flights. Helps prevent check washing! What is check washing? Check washing is a process where a thief erases the ink from a stolen check using common household products. Uni-ball Vision Elite Pens use specially formulated inks that contain color pigments that are absorbed into the check's paper fibers, "trapping" it from check washing efforts.