Make of cold-rolled steels,the surfaces is electroplated,which is and anticorrosion,strong and Enduring. This product can be folded 90 degrees and automatically in the open position through a spring activated within the hinge. Self-Lock folding hinges are easy to operate.You just clicking the latches and fold down for more space. Suitable for folding leg brackets of folding bed,sofas,dining tables,platforms,tables,coffee tables and other furnitures to facilitate better placement and portability. Easy installation and strong carrying capacity.