1. This series switch have normal and anti-pollute two difference models, it composed of frame,support insulator, with power part and operating mechanism. 2. Each pole have two pieces blade, there is press spring near the contactor base and have adjusted nut to keep good contact press, there is a support structure on the blade, it can be locked after closing, so it will not be closing by itself under any condition, under normal or short-circuit condition, it can ensure the reliable performance of dynamic and thermic stability.