From the Manufacturer:
For bold statements that need to go extra-wide, look to Sharpie Magnum Permanent Markers. This chisel marker includes an oversized tip for clear, precise, extra-wide marks. The intense black and red markers feature iconic Sharpie ink that is quick-drying and fade- and water-resistant, so your writing lasts for a long time. Durable, 3/4-inch felt chisel tip draws bold, highly visible lines. Specially formulated for both wet and oily surfaces, it is perfect for corrugate, wood, metal, foil, stone, plastic, leather and more. Durable aluminum body won’t roll or break.