For tracing paper, vellum drawing paper and lineboard. The rapidograph uses Rotring's unique capillary cartridge. The pressure-equalization system, including ink helix is part of the ink cartridge which ensures that every time you change the cartridge, you get a clean new ink helix. This means that you never need to clean the ink helix and top reliability is guaranteed.
Art Supplies from Jackson's | Rotring : Rapidograph | Jackson's Art Supplies - Jackson's Art Supplies - Finest Art Materials - Best Prices https://www.jacksonsart.com/brands/rotring/rotring-rapidograph