In the independent plastic cavity can be filled with 1.5~3MM thick steel lining. And according to the local wind pressure value, the height of the building, the size of the hole, window design to select the thickness of steel and profile series, in order to ensure the requirements of the building to the type of doors and Windows. Large sliding Windows or inward casement Windows are available for high-rise buildings with wind compression strength of more than six degrees. Low-rise buildings can choose outward Casement window or small size push-pull window, the wind pressure strength is generally at three levels.