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. Using a paint roller can save time compared to traditional brushes, especially for big projects. The roller can reach high places when used with an extension pole, making it easier to paint ceilings or tall walls. Proper technique and the right type of paint can enhance the finish and reduce the need for touch-ups.