This 8020 hardware is made out of zinc and works on any 1" x 1" or 25mm x 25mm t-slotted extruded aluminum bars. This l shaped bracket is a 90 degree inside hidden corner connector that provides a strong connection and is simple to install. No additional hardware required. This interior angle bracket comes with two set screws that require a 2.5mm hex wrench to tighten down properly (tool is not included). Top line quality control with tight tolerances and proper set screw threading ensures you will have perfect 8020 hardware every time these corner joint brackets are ordered. This 8020 corner bracket is great for home improvement projects, CNC, guarding, 3D printer, workbenches, lasers, stands, furniture, machinery, equipment, precision printers, woodworking and t tracks.