INKZALL™ Markers are built for tough jobs, staying sharp without mushrooming or pushing back under pressure. The acrylic nib writes on rough surfaces like OSB and concrete and continues marking even after 72+ hours with the cap off. Works on concrete, wood, metal, plywood, OSB, and plastic—even on wet, oily, dusty, or rusty surfaces. Quick-dry ink reduces smearing, while the thin body reaches tight spaces. Features include a helmet clip, one-hand easy-open cap, and anti-roll design to prevent accidental drops.