For a fountain pen, you need ink to fill. For a ballpoint pen you need a refill and for a mechanical pencil or a clutch pencil you will need a lead. For the Kaweco Sketch Up series are Highlighter leads available, which are a good alternative to throw away markers. High Quality refills by Pelikan, Faber-Castell, Kaweco, Waldmann and Otto Hutt are available. If you need help to find the right refill for your writing instrument, please contact our Service. We will be happy to assist you.