Aluminum T Bar, Custom Aluminum Tee Extrusions Manufacturer and Supplier
Source 40x120 aluminum extrusion profiles with t-shaped connector on m.alibaba.com
8020, 1010, 10 Series 1 Inch x 1 Inch T-Slotted Aluminum Extrusion DIY Extruded Linear Slot Bar Rail 80/20 (12" Long, Black Anodize): Amazon.com: Industrial & Scientific
E45-4545-C - 45mm x 45mm ALUMINUM T-SLOT EXTRUSION(Cut To Length)