This set of 3 hog bristle brushes is suitable for oil colour, acrylic colour and gouache. The set contains the following types and sizes: 3 flat brushes in sizes 4, 8 and 16. Hog bristle (also called bristle) is a sturdy type of hair used for thicker paints, such as oil and acrylic colours. The hair is strong and resilient and leaves a visible brush stroke in the paint.