The Uni Paint Marker is a popular oil-based marker designed to write on any surface and retain the vivid waterproof ink colour. PX-20 has a medium-fine acrylic bullet-shaped nib which writes a 2.2-2.8mm line. Valve-action marker writes on virtually any surface: glass, metal, wood, rubber, stone, plastic, paper, vinyl, leather, canvas and more. Quick drying ink marks opaque and glossy on light and dark surfaces. The archival-quality, acid-free, oil-paint ink is fade-, water, and abrasion-resistant, ideal for projects that need to last. Ink is permanent and certified AP-non-toxic. Bullet Tip - 2.8mm approx.