Diamine 30ml Autumn Oak fountain pen ink bottle. These 30ml Diamine Ink bottles are ideal to try out specific ink colours, to use when travelling or simply as a colour tester. Designed for all brands of fountain pens, with non-toxic water-based ink thats fast drying and creates a smooth design on the paper this ink is perfect for all writers. Made by Diamine, a British brand who have been based in Liverpool since 1864 the company is renowned for its quality and fantastic range of colours.