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