Businesses in plastics in primary forms manufacture or supply plastic materials before they are shaped into finished goods. These materials are usually supplied as pellets, granules, powders, flakes, pastes or liquids for use by manufacturers and processors. Common types include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyethylene terephthalate and engineering plastics such as polycarbonate and nylon. Materials may be made from virgin feedstocks or, where available, recycled sources. Products are selected for properties such as strength, flexibility, transparency, heat resistance and chemical resistance. Some businesses also blend polymers with colourants, stabilisers, fillers or other additives to produce compounds with specified characteristics. Customers may be able to obtain standard or tailored grades, along with technical information on processing and material performance.