MILWAUKEE INKZALL JOBSITE MARKER SETPack of 4 markers.Stays sharp, doesn't mushroom or push back under pressure.Acrylic nib ideal for rough surfaces such as OSB and concrete.Marker continues to write after 72+ hours of cap off time.For use on concrete, wood, metal, plywood, OSB, plastic.Can be used on wet, oily, dusty, rusty, with debris surfaces.Quick dry time - reduced smearing markings on PVC, metal surfaces.Thin body for use in restricted areas.Helmet clip - can be clipped to the construction site cap, trousers, overalls.Easy open cap for one hand operation.Lanyard hole, e.g. to attach the INKZALL highlighters to the belt.