The convenience of a brush pen meets the eco-friendly ink refillabilitiy in Pentel’s Art Brush Pens. The nylon brush tips and water-based dye ink combine to provide a smooth flowing ink that provides consistent colour over wide areas. Unless you don’t want it to, that is. These pens are easily blendable by touching the tips. As they are water-soluble, it is easy to lighten the tone by dipping the tip in water. Pentel Art Brush Pens come in 18 colours: Black, Red, Blue, Green, Lemon Yellow, Brown, Orange, Pink, Sky Blue, Light Green, Turquoise, Olive Green, Pale Orange, Steel Blue, Grey, Yellow Orange, Sepia and Purple. How to use These pens have a small red wedge between the ink cartridge and the grip that must be removed before you can use the pen. Compatible Ink Cartridges: Pentel Art Brush Pen Refill Cartridge.