Amazon.com: 2 2X2 Inch Square Plastic Plug Tubing End Cap 10 Pack, 2" 2"X 2" Black Square Tube End Cap Fence Post Pipe Cover Tubing Insert Chair Glide Finishing Plug : Industrial
1/2" x 4' Heavy Wall Square Clear Plastic Tube | VisiPak
Amazon.com: Prescott Plastics 1.25" Inch Square Plastic Plug Insert (4 Pack), Black End Cap for Metal Tubing, Fence, Glide Insert for Pipe Post, Chairs and Furnitures : Industrial & Scientific
ABS Plastic Pipe ABS Tube Square Plastic Tube, Suitable for Making Models and Decorations, 500 Mm in Length,Side Length:4mm(30pcs) : Amazon.ca: Industrial & Scientific
Amazon.com: Prescott Plastics 2.5 Inch Square Plastic Plug Insert, Black End Cap for Metal Tubing, Fence, Glide Insert for Pipe Post, Chairs and Furniture (10 Pack) : Industrial & Scientific