Flat brushes are painting tools characterized by their wide, rectangular bristles. They are commonly used in various art forms, including acrylic painting, watercolor painting, and oil painting. The flat shape allows for broad strokes, filling large areas quickly, and creating sharp edges for detailed work. These brushes come in different sizes, making them versatile for both large canvases and smaller projects. Artists often use flat brushes for techniques like blocking in colors, blending, and creating textures. Their design makes them ideal for both beginners and experienced painters looking to achieve specific effects in their artwork.