PVC is typically divided into three categories: Type 1, Type 2, and foamed or expanded PVC. Type 1 PVC is the most common kind, also known as rigid or U-PVC for 'un-plasticized'. Type 2 PVC, or fPVC, is made flexible through the addition of plasticizers. Foamed PVC is rigid, with a matte exterior. This lightweight form of PVC is most often found in signage.