The Uni-Ball Air Rollerball Pen has a unique, sleek tip, for smooth, legible writing at a variety of angles. The rounded tip varies the amount of ink released based on pressure and angle, for bold or fine lines. The vibrant ink is lightfast and waterproof for long lasting use. The medium 0.7mm tip produces a 0.52 - 0.86 line width. This pack contains 12 black pens.