Rotring Liquid Ink is designed for the Isograph technical pens, but can be used as drawing inks in their own right. offering a high density of pigment particles for optimum opacity and lightfastness. Both fast drying on media and waterproof, this ink is ideal for frequent drawers. Whether you\'re working on lineboard, tracing paper, or vellum drawing paper, Isograph Liquid Ink is an easy-flowing ink with excellent adhesion, so your lines turn out technically perfect every time. - Size: 23ml - Colour: Black - High density of pigment particles for opacity and lightfastness - Ink is fast drying on media for immediate results and is waterproof - Ink has adhesion for creating sharp and accurate lines - Can be used on multiple surfaces including vellum drawing paper, tracing paper and line board - Bottled pigmented ink is for refilling the isograph technical pen