INKZALL™ Markers stay sharp and resist mushrooming or pushback under pressure, making them ideal for tough jobs. The acrylic nib works on rough surfaces like OSB and concrete, and the marker continues writing 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, easy one-hand open cap, and anti-roll design to keep the marker from rolling off surfaces.