The size of an opening – 2100 * 1010 mm. The design has a thickness of a door cloth from 40 mm to 60 mm. The case of a cloth consists of two sheets of fire-resistant metal 0,8… 1,0… 1,2 mm thick, welded together. At the same time one of them is curved in a special way. It is filled with special fire-resistant heat-insulating material. The door box is made of a bent profile, at installation does not demand platbands.