La Perle des Encres or The Jewel of Inks, J. Herbin inks have long been a favourite of many fountain pen connoisseurs. Besides their wide range of colours, these inks are especially popular due to the use of entirely natural dyes. The use of these dyes mean that these inks are of a neutral pH (non-acidic) and fast-drying. These are short international standard ink cartridges so will fit most fountain pens from many leading brands. Pack of 6 cartridges, presented in a tiny, neat cylindrical metal tin. J. Herbin started producing ink in 1670, making ink for Louis XIV, the Sun King (or Le Roi Soleil ) and other important French figures such as Victor Hugo (author of "The Hunchback of Notre Dame" and "Les Miserables"). The "Blue of the Depths" ink is of an exceptional quality rich in colour and of an incredible texture. This ink offers unparalleled writing quality. Perfect for writing enthusiasts and lovers of beautiful letters! AQUARELLABLE: diluted in water, it offers a delicate and homogeneous colour gradient. Applied with a brush, the ink sublimates your drawings. COMPOSITION: The ink is composed - water, - humectant (which limits the drying of the feather), - as a preservative (which preserves the quality of the ink over time). COMPATIBILITY: It is specially formulated for fountain pen and rollerball pen use. It is indeed finely filtered so as not to clog the pens. 6 cartridges - Universal format. Made in France