Copic Sketch markers are high-quality professional illustration tools, perfect for architectural design, product rendering, and other forms of industrial design. They are also great for hobbyists for use with models, drawings, and similar projects. Numerous colors are available. The inks are alcohol-based for a long shelf life, and many colors are refillable. Each marker is double-sided, with a Medium Broad nib on one end and a Super Brush nib on the other.