Its special graphite lead makes marking possible on almost all surfaces, no matter if dry or wet, glossy or rough, dusty or oily. Wipe clean from glossy surfaces with a damp cloth. Most versatile capabilities due to special colour leads: for bright or dark surfaces, in water-soluble or permanent. Convenient quiver-cap with special clip for perfect one-hand handling. Patented: The integrated sharpener in the quiver-cap - always and immediately at hand. High value push mechanism for automatic lead feed in a stainless steel tube. Leads most easy to refill from the back end. Extremely long lasting and sustainable due to high quality manufacture and refill ability.