1. The frame should be a quality metal structure. Depending on how much stiffeners contains, its strength also depends. Typically, the frame is welded to the steel shield, the thickness of which is at least two millimeters.
1. The frame should be a quality metal structure. Depending on how much stiffeners contains, its strength also depends. Typically, the frame is welded to the steel shield, the thickness of which is at least two millimeters.