INKZALL™ markers are built to perform in tough conditions, staying sharp without mushrooming or pushing back under pressure. Their acrylic nibs write on rough surfaces like OSB and concrete, and continue marking even after 72+ hours with the cap off. Suitable for concrete, wood, metal, plywood, OSB, and plastic—even on wet, oily, dusty, or rusty surfaces. Quick-dry ink reduces smearing on PVC and metal, while the thin body reaches restricted areas. Features include a helmet clip for easy carrying, one-hand open cap, and an anti-roll design to prevent accidental drops.