Tangshan Porcelain Insulator company Co., Ltd which is built in 1952, the predecessor is "Tangshan High Voltage Porcelain Factory". In 2003 it succeeded the remanufacture is the limited liability company, the establishment "the Tangshan city porcelain insulator limited company". It is the biggest rod insulator enterprise in China. As a professional porcelain insulator company, it concentrates on the development, design, and manufacturing of 126kV~1100kV rod insulator, ±500kV.±800kV DC rod insulator and 126kV~550KV SF6 porcelain shell etc. High quality, wide range of products and high working efficiency make it is one of the key enterprises in China insulator industry. The product trade mark is "TD".