Ceramic insulator is also called Porcelain insulator. Disc ceramic insulators are designed to link together into strings, typically of two or more, to provide much higher voltage protection than any single insulator. Disc ceramic insulators are typically used on high tension power transmission towers as shown below. Porcelain/ceramic is by far the most commonly used insulating material but there are a number of glass styles as well. Porcelain/ceramic disc insulators revolutionized the power distribution industry allowing much higher voltage protection *- there are several 1,**0kV DC transmission lines utilizing suspension insulators.