The insulators are composed of porcelain parts and upper and lower metal attachments bonded with adhesive. The porcelain part ends have elastic pads under the bonding contact areas with the metal attachments. The bonding sections of the porcelain parts feature structures such as sanding, knurling, and grooving, which enhance mechanical strength, prevent loosening, and twisting. The porcelain surfaces are evenly glazed with white enamel, and the metal attachments are coated with gray magnetic paint. The main structures of the porcelain insulator bodies include hollow partition (piercing type) and solid (non-piercing type) structures. The bonded pillar insulators are generally solid non-piercing type structures, which require less maintenance and testing work than the former. The porcelain insulator bodies come in two shapes: multi-angled or less-angled. The multi-angled shape increases the surface distance and has better electrical performance, with the exception of the outer bonding pillar insulators, which are being phased out, all other products are multi-angled. The internal bonding structure, due to the metal attachments being bonded into the porcelain holes, increases the insulation distance and improves the electrical performance, while also reducing the space required for installation. However, since internal bonding is not favorable for enhancing mechanical strength, insulators requiring high mechanical strength are best suited for combined bonding (i.e., the upper attachments use internal bonding, and the lower attachments use external bonding).