A paint roller is a tool used for applying paint to large surfaces quickly and evenly. It consists of a cylindrical foam or fabric cover attached to a handle. The cover absorbs paint and allows for smooth application on walls, ceilings, and other flat areas. Paint rollers come in various sizes and textures, making them suitable for different types of paint and surfaces. Using a paint roller can save time compared to traditional brushes, especially for big projects. To achieve the best results, it's important to choose the right roller cover for the specific paint type, such as latex or oil-based paints, and to use a paint tray for easy loading.