Record results in lab notebooks, fill in charts, draw graphs, mark recording paper, and produce diagrams. Pen's unique, long leg lays flat against rulers and flexible curves for accurate alignment. This precision pen is perfectly balanced to feel good in your hand. Instant writing, long storage time, and dry-out prevention are ensured by an airtight ring seal in the cap. Pen responds the moment it is touched to paper. Smooth-flowing, fade-proof ink is a patented formulation. Instant-drying ink eliminates smearing and bleeding. Extra-large ink reservoir assures half-mile write out. Colors are ultra-black (opaque black for making superb photocopies), vivid red, blue, and green. Perfect and precise lines are drawn at first stroke with the long-legged, highly polished stainless-steel point tube. Durable wear-free plastic tip glides smoothly across a page. Tip stays sharp‚Äîwon't "mush up". Narrow line is sharp, precise, clear, and constant. Line sizes are 0.2 mm and 0.4 mm. Order an assortment and a pack of your favorite color.