Amazon.com: Prescott Plastics 1.5 x 3 Inch Rectangle Plastic Plug Insert (4 Pack), Black End Cap for Metal Tubing, Fence, Glide Insert for Pipe Post, Chairs and Furniture : Industrial & Scientific
Rectangular Plastic End Cap 1in x 2in Rectangular | P64-U96-WH
White PVC rectangular pipe for construction
Braided Carbon Fiber Rectangular Tubing ~ 2" x 1" x 96" | DragonPlate
3/4" OD x 5/8" ID Clear Extruded Square Acrylic Tubing | U.S. Plastic Corp.
PVC GRAY RECTANGULAR CHANNEL Plastic Sheet - Mobile
Plastic 1/2 x 1-1/2 inch Black Rectangle Tubing Cap, Finishing Plug, Pipe Tubing End Cap, Durable Chair Glide Universal - 20 - Walmart.com
MOCAP Plastic End Cap Tube Plugs for 1" X 2" OD Rectangular Tube - Black (100 pcs.) - Walmart.com
Amazon.com: Rectangle Black Plastic Plug End Cap - 1" x 1/2” Rectangular Tube Caps - Rectangle Tubing End Cap Plug - Plastic Plugs for Rectangular Tube - Rectangular Hole Plug - Rectangular
Clear Square Polycarbonate Tube | U.S. Plastic Corp.
Custom Plastic Tubes and Tubing Manufacturer | Lakeland Plastics
Friedrich and Dimmock Glass F&D Clear Fused Quartz Rectangular Tubing - Friedrich and Dimmock Glass
Braided Carbon Fiber Rectangular Tubing ~ 2" x 4" x 48" | DragonPlate
USA SEALING Bulk-RPT-PVC-8 PVC Rectangular Tubes, 1-3/8" Outside Height, 3.346" Outside Width, 6 ft. Long: Amazon.com: Industrial & Scientific