This product is the second purchase. For the first time metal parts of the decorations immediately fired. In addition, the deformation becomes intense within use. As a countermeasure, the metal part frequently uses chorus stopper. Before deforming, affix an acrylic plate bent in an L shape on the back side of the lid, and bend the long acrylic board cut into the width of the inside of the back into the U shape by bending it in the body part. The pasted part must be glued unless you select an adhesive. Acrylic board to be processed in L shape is black, if possible. This will eliminate worry about shape collapse.