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
IRWIN Industrial: News and Events: Tubing Plugs & Caps
End caps, plugs, tube inserts, hand grips | StockCap Australia
Hillman 2-Pack 1/2-in x 1/2-in Black Plastic End Caps in the End Caps & Screw Protectors department at Lowes.com
Round Plastic End Caps
Connect-It End Caps - Metal Mate
10/50/100pcs Rectangular Plastic End Caps for Steel Tubing - Big Range of Sizes | eBay
Plastic Blanking End Caps | Plastic Square Cap Ends | Plastic Inserts | Tool Parts - 10/50 - Aliexpress
150x50mm Rectangle Tube End Cap (ENDCP150X50) - Richmond Wheel & Castor Co
Rectangular Tube Plastic End Cap | Retail Wall Standards | By Grand + Benedicts Store Fixtures
Formufit 1/2 in. Furniture Grade PVC Internal Dome Cap in Yellow (10-Pack) F012IDC-YE-10 - The Home Depot
Square Tube End Caps - Plastic Square-Shape Tube End Caps
Tubing Caps 3" Square Black Plastic end caps for square tubing 3x3 8-1 – JSP Manufacturing