Great to create dotting references for cytology Fine tip permanent markers Writes on any surface including glass, ceramic, and metal Available in red, black, green, and blue 12 per box Dotting pens will write on prepared slides for histology and cytology. Great to create dotting references for cytology. These fine tip permanent markers are waterproof and write permanently on almost any surface including glass, plastic, ceramic and metal. Available in red, black, green, and blue. Sold by the dozen per color.