Models are also sometimes cast in polyurethane resins. Resin shares some of the advantages as plastics over metals. They are lighter, so can make larger models, can cast higher levels of details, and will often require less preparation before painting than metals. This makes resin a common choice for smaller manufacturers of larger scale models with high levels of details intended for display or competition painting, where resin casts can match the details of plastic models whilst still being affordable for smaller production lines. However, resins are often more brittle than plastics, with small details likely to break so, whilst smaller scale resin models are still produced where the productions are small, plastics are still favored by most manufacturers for smaller and mass-produced models.