The main ingredient in all composite shingles is asphalt. The difference is what's inside. Class "A" shingles have a fiberglass mat that is saturated with asphalt and colored granules are installed on top to protect the asphalt and to provide an esthetically pleasing look. Class "C" shingles are what where most commonly referred to as asphalt shingles, they have a felt or paper core that are saturated in asphalt and colored granule installed. Almost all shingles manufactured today are Class "A" asphalt shingles. The "A" denotes the fire rating.