The Insulator Museum of the firm NGK Insulators, located in Japan, is the only ceramics museum of porcelain insulators in the world. The museum contains some unique items, including a "pin insulator for communication" manufactured in 1875 that is believed to be the oldest domestic Japanese insulator. It has "approximately 5000 pieces of insulators and maintenance tools from 21 countries... and 57 manufacturers." About 300 pieces are on display at any one time. It also has a detailed and informative display on the material, processes and applications.
NGK Insulators itself is a notable company; it is the world's largest manufacturer of electrical porcelain, with a number of plants in different countries. Due to the company's significant production of ceramic items, its annual sales exceed $USD3.5 billion. NGK Insulators has been producing porcelain continuously for nearly 100 years, and, sometime in the mid 1980s, its total output surpassed 150 million porcelain units.