Acrylonitrile Butadiene Styrene, or ABS plastic, is a thermoplastic. It is an amorphous polymer comprised of three monomers, acrylonitrile, butadiene and styrene. ABS is a plastic made of acrylonitrile, butadiene and styrene. It is called engineering plastic because it is a material with higher mechanical and thermal properties than conventional plastics, which also means that it is more difficult to print. ABS is a common thermoplastic used to make light, rigid, molded products such as pipe, automotive body parts, wheel covers, enclosures, and protective head gear.