Our Black Adjustable Shelf Brackets are designed to provide strengthe and versatile support for glass or wood shelves ranging from 1/8 to 15/16 inch (3 to 24 millimeters) thick. With a depth capacity of up to 10 inches (254 millimeters), these brackets offer ample space for displaying your belongings. Each package contains two shelf brackets, providing balanced support for your shelves. The brackets are secured with a screw to the substrate, and an adjustment screw is included to accommodate different glass thicknesses. With a height of 2-1/16 inches (52 mm) and a shipping weight of 1 lb (454g), these brackets offer sturdy support while blending seamlessly into your space. It also comes with a 1-year warranty, ensuring your satisfaction and peace of mind. *For optimal strength in drywall installations, we recommend securing the brackets to a stud no more than 16 inches (406 millimeters) apart. In concrete installations, it is advisable to use high-quality anchors. The material behind the bracket can affect its performance, with hard materials like concrete, tile, or marble being less prone to denting or collapsing. However, drywall may compress or dent over time, potentially causing the front edge of the shelf to slant downward. Therefore, when installing in drywall, consider the shelf's depth and weight capacity.