Insulators are categorized by their installation methods, including suspended insulators and pillar insulators; by the type of insulating material used, they can be porcelain, glass, or composite (also known as synthetic) insulators; by the voltage class, they are divided into low-voltage and high-voltage insulators; by environmental conditions, there are pollution-resistant insulators for dirty areas; by voltage type, there are DC insulators. Additionally, there are various special-purpose insulators, such as insulating crossarms, semiconductor glaze insulators, tension insulators for distribution, reel insulators, and wiring insulators. Furthermore, they are classified into two types based on the possibility of insulation breakdown: Type A, non-breakdown insulators, and Type B, breakdown-insulators.