The Staedtler Triplus Fineliner Pens are perfect for precise writing and drawing. These pens feature a superfine 0.3mm tip that allows you to create precise lines and details in your artwork. The pens are also water-based and acid
From Wikipedia
Staedtler SE is a German multinational stationery manufacturing company based in Nuremberg. The firm was founded by J.S. Staedtler (1800–1872) in 1835 and produces a large variety of stationery products, such as writing implements, art materials, and office supplies.