Efficient for the environment. STAEDTLER develops clever product solutions that are not only environmentally friendly but also user-friendly. Blocked tip: Even under exceptionally strong writing pressure, the tip of the marker remains blocked and cannot be pushed into the casing. Suitable for paper, fax, and carbonless copy sets. High lightfastness: Writing remains legible even after years. Easily refillable with a refill station. Inkjet safe: All colors do not smudge on inkjet prints and handwritten texts. Copy safe: Violet and turquoise for originals that need to be copied. Twist cap for easy opening. Airplane safe: Automatic pressure equalization prevents the pen from leaking on airplanes.