Nylotube® Black Flexible Nylon 12 Tubing | U.S. Plastic Corp.
Square Plastic Black Blanking End Cap Tubing Pipe Insert Plug Bung Black/White Insert For Chair Leg Pipe 15mm ~ 100mm Furniture
Amazon.com: 12 Pack 1.25 Inch Square Tube End Cap Plastic Plugs, 1.25"x1.25" Square Tubing Plug, Tube End CapsTubing Post End Cap Suitable for Square Tube Square Plastic Plug, Tubing Post End Cap
Amazon.com: Prescott Plastics 1 1/2” (38.1 mm) Square Plastic Plug Insert, Black End Cap for Metal Tubing, Fences, Glide Protection for Chairs and Furniture (4 Pack) : Industrial & Scientific
Amazon.com: Prescott Plastics 1.5" Inch Square Plastic Plug Insert (4 Pack), White End Cap for Metal Tubing, Fence, Glide Insert for Pipe Post, Chairs and Furniture : Industrial & Scientific
Amazon.com: Suiwotin 4Pack 100mm (4 Inch) Square Plastic Plug, Square Tubing End Caps, Tubing Post End Cap for Square Tubing/Black Plastic Square Plugs : Everything Else