This Alloy Hinges for 2020 Series 6mm T-Slot Aluminum Extrusion Profileused to connect two profiles. Get swinging with this handy alloy hinge, attach it to your 20mm extrusion and you can have parts that swing open 180 degrees. Using our button screws, the bumpy heads make it close around 170 degrees, you can substitute countersink screws if you want a full 180.