Inkzall, 4 Pack, Black, Fine Point, Marker, Clog Resistant Marker Tip, Writes Through Dusty, Wet and Oily Surfaces, Durable Marker Tip For Writing On Concrete, Sob and Rough Surfaces, Built In Hard Hat Storage Clip, Ink Dries In Seconds, Lanyard Hole, Anti Roll Body Design, Non Toxic Ink.