Steel,HIGH QUALITY MATERIAL - These 12in metal shelf brackets made of premium cold-rolled steel, thickness metal sheet with smooth surface, no rough edges, solid and sturdy, well made and fairly strong for heavy duty.,ABOUT THE SIZE - The size of the heavy duty metal bracket is 10x12 inch, the long screws that install on the wall part is 0.16 x 1.18 inch [ Total 72pcs] ,the short screws which mounted on the shelves part is 0.16 x 0.63 inch [ Total 72pcs] suitable for shelves with thickness no less than 4/5 inches / 20mm.,EASY INSTALLATION - Each wall mount shelf bracket comes with pre-drilled screw holes to guide you through the process, and comes with complete hardware screws for quick and easy to install the shelf bracket.,WIDELY APPLICATION - These 12-inch white shelf brackets are perfect for DIY shelves to saving space, use in home, bathroom, shop, garage, or business, support floating shelves for your books, potted plants, and all kinds of home items.,BUY WITH TOTAL CONFIDENT - If you have any question with the 12 x 10 inches L-shape shelf bracket, please feel free to contact us through Amazon for details on how to set up and use the device.