This uni-ball prockey permanent marker has a dual-ended design with a fine bullet tip on one end and a medium bullet tip on the other. It contains permanent ink and can be used to mark on a variety of different surfaces. It has a 0.9 Mm bullet tip on one end and a 0.4 Mm nib on the other. It's suitable for use on paper, plastic, metal, glass and more. The water-based ink is designed to dry quickly to prevent smudges and smears. It features a handy pocket clip so you can carry it on the go.