430052 | Square tube connectors -Technopolymer and steel, STC Type | ELESA | MISUMI
E00791 Pivotable Stainless Steel Pivotable Connector for 1/2" Bar w/ Set Screws for Square Tube. External diameter 7/8". This INOX Stainless Steel Connector has a pivotable connector and features a 0.01" hole
6 PCS 1 Inch T Square Tube Clamp Connector 201 Stainless Steel 2 Way Square Pipe | eBay
6 Sets 1 Inch Square Tube Clamp Connector, 201 Stainless Steel 3 Way 90 Degree Vertical Square Chain Fence Guardrail End Rails Clamps for 25mm Square Pipe, Thickness 1.7mm(Bolts/Nuts Included) - Amazon.com