TREBORK supplies square plastic end caps for finishing open ends of square steel tubes, box sections and fence posts across the UK. Choose from flat ribbed tube inserts, pyramid top inserts and external post caps. Buy from one piece, with no minimum order.
Our square tube end caps fit inside hollow square tubing. Also known as square plastic bungs, ribbed inserts, tube end plugs and box section blanking plugs, they use ribs to grip the inner walls while the top covers the cut end of the tube.
They are used on furniture frames, chair and table legs, workshop equipment and other square tube assemblies. Black, grey and white options are available in selected sizes. The range includes variants for different tube wall thicknesses, including thicker-walled profiles and selected rounded-corner designs. Check the individual product options for the required combination.
Square pyramid plastic end caps combine an internal ribbed fitting with a raised pyramid-shaped top. They provide a decorative finish for open square tubes, including metal fence posts and railings. Select the size and wall thickness on the product page.
Square fence post caps fit over the outside of the post. These external plastic caps, also called square ferrules or post covers, cover the open top and overlap the outer sides of the tube. Choose them by the outside dimensions of the square post.
For internal inserts: measure the outside width of the square tube and its wall thickness. For example, a 25 × 25 mm tube needs an insert listed for that outside size and a compatible wall thickness.
For external caps: measure the outside width of the post and compare it with the fitting size shown on the product page.
Tube inserts are not hole plugs: ribbed inserts need sufficient tube depth for their ribs to grip. They are not suitable substitutes for plugs designed to close holes in thin sheet material.
Each product page includes available options, a dimension table and fitting information. Sizes marked “Available to order” can be requested by emailing info@plasticendcaps.co.uk for price and lead time.
