Marvy DecoFabric markers have a 3mm fine bullet point that works great for details! The opaque formula in the markers is great for use on dark colored items and heavy fabric like denim, but also works well on cottons. Marks are lightfast and water-resistant when dry. Always try out your markers on test fabric or an inconspicuous area first. Apply to pre-washed fabrics. Let dry overnight and then heat set with an iron to make the marks permanent. Wash/dry on delicate setting. Ink is acid-free, odorless, and non-toxic.