It is the most widely used filler for plastics. It is inexpensive and can be used at high loadings. It is generally used as an extender; however, it can improve stiffness and impact strength, especially with fine particle grades. It is not only used with several thermoplastics, such as PVC (e.g., in PVC pipes and floor tiles), but also with thermosets such as polyesters (in sheet molding compounds).