The Pentel Aquash Water Brush Medium has a built-in 10ml water reservoir that pushes water out through the brush tip with a simple squeeze. These brushes are great for outdoor artist, and can be used for watercolour work, line and wash, water-based marker pens or watercolour pencils. The nylon brush tip is hard-wearing and the Medium sized tip can be used for both fine detailed work and for larger washes and areas of colour. Great for painting holidays and creating art while traveling.