Amazon.com: Rectangle Black Plastic Plug End Cap - 4" X 2” Rectangular Tube Caps - Rectangle Tubing End Cap Plug - Plastic Plugs for Rectangular Tube - Rectangular Hole Plug - Rectangular
Econoco RE2 Rectangular Tubing, 2' Length x 1/2" x 1-1/2" (Pack of 10): Amazon.com: Industrial & Scientific
Amazon.com: Econoco Commercial Rectangular Tubing Face-Out, 12", Black (Pack of 24) : Industrial & Scientific
Amazon.com: Only Garment Racks Black Gridwall"T" Base Rectangular Tube with Levelers (Economically Sold in a Set of 3 Pairs) Black Finish (1918 Black Legs - (3 Pairs)) : Industrial & Scientific
Amazon.com: DBM IMPORTS 10 PC 12" SLATWALL HANGRAIL Bracket Holding 1-3/4" x 1/2" Rectangular Tube for Retail Display - Chrome : Industrial & Scientific
Kaka Industrial 1-1/2"x 14 gauge Tubing Rolling Bender TR-40 with multiple passes square tubes Mild Steel Cooper and Aluminum,Manual Square and Rectangular Tube Bender - - Amazon.com