Insulators are made of porcelain parts and upper and lower metal accessories, which are glued together. The end face of porcelain parts and the contact parts of metal accessories are cushioned with elastic gaskets. The adhesive parts of porcelain parts are sand mounted, knurled, grooving and other structures respectively to ensure mechanical strength and prevent looseness and torsion. White glaze is evenly applied on the surface of porcelain parts, and grey enamel is applied on the surface of metal accessories. The main structure of insulator porcelain is divided into two types: empty cavity baffle (breakable type) structure and solid (non-breakable type) structure. Generally, post insulators with combined adhesive are of solid core and non-breakable structure. The latter structure improves the safety and reliability and reduces the maintenance and test workload compared with the former. There are two kinds of porcelain insulators with multi-edges or less edges in appearance. Multi-prism increases the distance along the surface, and its electrical performance is better than that with less prism. Except for the post insulators with external glue installation that will be phased out, all the other products are multi-prism. Binding structure, because the metal accessories glue into the porcelain hole, the corresponding increase the insulation distance, improve the electrical properties, but also reduces the installation of space position, but because of the rubber to improve the mechanical strength is bad, so the mechanical strength to demand higher insulation, appropriate USES joint binding (namely inside using glue on the attachment, attachment outside using binding).