The TGS-12-40.5 gas-insulated switchgear (referred to as C-GIS) is a fixed switchgear with SF6 gas insulation, a metal enclosure, and a fixed configuration. It is designed for three-phase AC 50/60Hz single bus and busbar sectionalizing for indoor assembly. This equipment can be applied in various scenarios, including power generation plants, small and medium-sized generators, substations, high-rise buildings, industrial enterprises, subways, and electrified railways, enabling control, protection, and monitoring of the power supply system and loads. It is particularly suitable for use in underground, high-altitude, permafrost, coastal, humid environments, and densely populated areas.