Brustro Artists Greengold Acrylic Brush Flat Series 1800, Size – 4

The flat brush very closely resembles a wash brush, except it is not quite as thick and the bristles are typically not as rounded on the edges.
Brustro Greengold Flat brushes are great for thin to wide strokes where you want a lot of paint coverage.
Flat brushes can also be used for thick to thin lines. Flat or rectangular brushes have square, flexible ends and can hold a lot of paint. When used flat, they can make long strokes and are well suited to blending and painting in large areas.
The tip and sides can also be used for more delicate lines and small touches.