Rectangular Hollow section steel 100mm x 60mm x 3.5mm
4 Pack Square Tube Inserts 100mm x 100mm, White, Box Section Caps, Tube End Cap | eBay
Trebork - Square Tube Inserts Plastic End Caps Plugs Black, Grey & White
Plastic Tube Insert Plugs, 12PCS Rectangular Square End Caps Black Plastic Inner Plugs Pipe Tubing Post End Cap for Box Section Rectangle Tube (40mm*80mm) : Amazon.co.uk: DIY & Tools
100 x 100mm Square Hollow Section 3.8m - NVF Wrought Iron Components