Standard 90 bending In order to ensure that each shelf bracket can be at 90 to the maximum extent possible, we add a rigorous picking process before the shelf brackets are packaged. The standardized 90-degree design is so important that it s the objective factor in ensuring that items remain level and do not tip over after being placed on the board(board is not included). Heavy Duty Iron & Durable Coating Our floating shelf hardware is made of thick, heavy-duty iron, stamped and bent in one piece, no welds are not easy to break with better toughness. Each pair of floating shelf bracket can hold up to 160 pounds of weight. The surface is covered with a thick layer of black frosted coating. It increases the friction between the board and the bracket, on the other hand, it is more waterproof and less prone to rust, which prolongs its service life.