An asphalt shingle uses asphalt for waterproofing and is one of the most widely used roofing covers because it has a relatively inexpensive up-front cost and is fairly simple to install. Asphalt shingles are composed of: a base material (organic felt or glass-fiber mat, that provides support for the weather-resistant components and gives a shingle strength); asphalt and fillers; and surfacing material (generally in the form of mineral granules, that provides protection from impact and UV degradation and improves fire resistance). The most common form are strip shingles, usually with three tabs (3 tab strip shingles). Shingles may be produced in a single layer or two or more layers. The latter generally are known as laminated strip shingles, or architectural shingles, and they have a three dimensional appearance.