Inkzall, 4 pack, black, fine point, marker, clog resistant marker tip, writes through dusty, wet & oily surfaces, durable marker tip for writing on concrete, sob & rough surfaces, built in hard hat storage clip, ink dries in seconds, lanyard hole, anti roll body design, non toxic ink. The durable permanent marker tips are designed for writing on rough surfaces such as OSB, cinderblock, and concrete, and the ink dries quickly to reduce smearing. The construction marker also has a built-in hard hat clip providing you with easy storage and access. You can leave the marker cap off for up to 72 hours and the fine tip will remain completely functional. Our MILWAUKEEยฎ INKZALLโข markers showcase our relentless mission to provide you with innovative solutions and commitment to best-in-class durability.