This Ecoline Brush Pen Set of 5 Grey Tones contains transparent watercolour pens which are perfect for drawing & illustration. The pens are filled with transparent dye ink & gum arabic which can be combined with watercolours. Great for digital artwork thanks to their consistent vibrant colours. ideal to be used with card, paper, watercolour paper & board. You can thin the ink to create colourful washes. The colours are not waterproof so they can be re-worked once theyve dried. The 5mm brush nib allows for a range of mark making by applying different pressures. Odourless & fast drying, perfect for on the go painting. Not particularly light-fast, Ecoline advise keeping artwork in a portfolio for best colour retention. Colours Included Warm Grey Cold Grey Light Warm Grey Deep Grey Grey