●2020 Series Aluminum Profile Connector Set widely used for building industrial aluminum frame structures, 3D printers, CNC Routers, CNC laser cutters, Robotics Projects. ●Package Content: 20pcs 2020 Series Aluminum Extrusion Connectors,40pcs Carbon Steel Galvanized M5 x 8mm T-slot Nuts, 40pcs stainless steel M5x8mm Hex Socket Cap Screw Bolt, 1 piece 3mm wrench. ●Aluminum Corner Bracket used to connect pieces of 20mm aluminum extrusion at a 90 degree angle suitable for most of metric 20 Series Aluminum Profile Extrusion. ●Black stainless steel hexagonal screws, more rust resistant, no oil stains. ●T-Slot Aluminum Extrusion M5x8mm Hardware Slide In T-Nuts made from high quality carbon steel Galvanized.