• Natural – made with mohair or lambswool; best with oil-based paints.

• Synthetic – made with nylon, polyester, or a combination; best with water-based paints.

For latex paint, you should use synthetic materials only. For oil-based or alkyd paints, you can use either synthetic or natural material. As with brushes, it’s always a good idea to check the manufacturer's recommendations before purchasing.

Nap (or pile) is the length of the roller's painting surface. Lengths will vary from 1/16 inch to 1-1/2 inch. If you're painting a smooth surface, choose a short napped roller. For a rough surface such as masonry, use a longer nap. Rollers with textured surfaces are also available for special finishes.

Rollers come in widths from 4 to 18 inches. The metal frame for the roller cover comes in two types - birdcage and metal. The birdcage frame works better if you're using fast-drying paints, as it cleans up more easily than the solid-metal type. Most handles are made for attaching an extension.

Trim rollers come in varying shapes and sizes. Cone-shaped types work well in inside corners. Doughnut-style rollers are good for mouldings and other fine work.