These rectangular plastic end caps fit inside open rectangular tubes and box sections to give furniture, metal frames and fabricated assemblies a neat finish. Made from low-density polyethylene (LDPE), the inserts have a ribbed stem that fits inside the profile while the head covers the cut end. They are also known as rectangular tube bungs, rectangular tube inserts or plastic tube end plugs.
Choose your tube size, compatible wall thickness and colour using the product options above, then enter the quantity you need. Black, grey and white options vary by size and variant. There is no minimum order: buy one replacement or quantities for your project. Check your selected variant for its price, availability and applicable quantity discounts.
Use these ribbed inserts as rectangular box section blanking plugs to finish suitable chair and table legs, bench frames, workshop furniture, fencing components and other metal fabrications. They close exposed tube openings and cover the cut tube end, making them useful for both new assemblies and replacement parts.
For other profile shapes, see our square plastic end caps and round plastic end caps.
Measure the outside width and depth of the rectangular tube and its wall thickness, then match all three measurements to the same row in the table. The listed tube dimensions refer to the outside of the profile, not its internal opening.
For example, a tube measuring 20 x 40 mm externally with a 2.0 mm wall thickness falls within the listed 20 x 40 mm insert’s compatible wall thickness range of 1.0–3.0 mm.
Some sizes have more than one fitting option. The two 10 x 20 mm inserts in the table have different wall thickness ranges and fitting dimensions, so check the exact variant before ordering.
Measure straight across each outside dimension of the tube. If you start at the 10 cm mark, subtract 10 cm from the final reading: a reading from 10 cm to 14 cm gives 40 mm. Use callipers for wall thickness measurements that are too small to read accurately on a tape.
Check both outside dimensions and the wall thickness before ordering.
All dimensions below are in millimetres. The outside dimensions identify the tube size, and W gives the compatible tube wall thickness. Use the drawing alongside the table to compare the remaining product dimensions. Check the product options above for sizes currently available to order.
Use the colour buttons to select a matching tube size, wall thickness and colour. Check the selected variant’s availability before ordering. Sizes without colour buttons are available to order. Contact TREBORK to confirm the required size, colour, quantity, price and lead time.
| TYPE | Outside | Choose colour | Wall Thickness | mm | mm | mm | mm | mm |
|---|---|---|---|---|---|---|---|---|
| Dimensions | View variant | W | A x B | C | H | E x F | F x J | |
| Rectangle End Cap | 10x20mm | Black | 0.8–1.0 | 20x10mm | 3.0 | 12.0 | 6.1 x 15.9 | 9.0 x 19.3 |
| Rectangle End Cap | 10x20mm | Black | 1.0–1.5 | 20x10mm | 3.0 | 12.0 | 5.7 x 15.8 | 8.4 x 18.5 |
| Rectangle End Cap | 10x25mm | Black | 1.0–2.0 | 25x10mm | 5.0 | 11.5 | 6.4 x 21.5 | 8.7 x 23.5 |
| Rectangle End Cap | 10x30mm | Black | 1.0–1.5 | 30x10mm | 3.1 | 12.8 | 4.9 x 24.4 | 8.8 x 28.7 |
| Rectangle End Cap | 10x35mm | Black | 1.2–2.5 | 35x10mm | 5.0 | 10.0 | 5.0 x 29.5 | 7.4 x 32.0 |
| Rectangle End Cap | 10x40mm | Black | 1.5–2.0 | 40x10mm | 2.8 | 13.1 | 4.9 x 34.3 | 7.6 x 37.8 |
| Rectangle End Cap | 11x70mm | Black | 1.0–2.0 | 70x11mm | 3.5 | 20 | 5.2 x 61 | 9.7 x 68.5 |
| Rectangle End Cap | 15x20mm | Black Grey White | 1.0–2.5 | 20x15mm | 5.0 | 11.0 | 10.8 x 15.5 | 14.0 x 19.0 |
| Rectangle End Cap | 15x25mm | Black Grey White | 1.0–2.0 | 25x15mm | 5.0 | 12.9 | 10.3 x 19.9 | 13.9 x 23.9 |
| Rectangle End Cap | 15x30mm | Black | 1.0–2.0 | 30x15mm | 3.8 | 14.8 | 10.9 x 23.1 | 13.5 x 28.8 |
| Rectangle End Cap | 15x35mm | Black | 1.0–2.5 | 35x15mm | 5.0 | 12.3 | 9.7 x 30.3 | 13.1 x 33.1 |
| Rectangle End Cap | 15x40mm | Black | 1.2–2.5 | 40x15mm | 4.2 | 13.0 | 8.3 x 33.5 | 13.5 x 38.6 |
| Rectangle End Cap | 15x45mm | Black | 1.0–2.5 | 45x15mm | 5.0 | 11.1 | 10.4 x 40.2 | 14.0 x 43.4 |
| Rectangle End Cap | 15x50mm | Black | 1.0–2.0 | 50x15mm | 5.0 | 13.7 | 10.6 x 45.6 | 13.8 x 49.5 |
| Rectangle End Cap | 18x30mm | Black | 1.0–3.0 | 30x18mm | 5.0 | 14.0 | 11.0 x 22.6 | 16.5 x 28.5 |
| Rectangle End Cap | 20x24mm | Black | 1.0–2.5 | 24x20mm | 4.2 | 14.2 | 12.8 x 13.5 | 18.4 x 23.6 |
| Rectangle End Cap | 20x25mm | Black | 1.0–2.5 | 25x20mm | 5.0 | 14.6 | 12.0 x 17.1 | 18.1 x 23.1 |
| Rectangle End Cap | 20x30mm | Black | 1.0–3.0 | 30x20mm | 5.0 | 14.0 | 13.0 x 22.5 | 18.5 x 28.5 |
| Rectangle End Cap | 20x35mm | Black | 1.0–3.0 | 35x20mm | 5.0 | 13.0 | 13.1 x 28.3 | 18.0 x 33.2 |
| Rectangle End Cap | 20x40mm | Black Grey White | 1.0–3.0 | 40x20mm | 5.0 | 14.0 | 13.0 x 32.6 | 18.5 x 38.5 |
| Rectangle End Cap | 20x50mm | Black | 1.0–3.0 | 50x20mm | 5.0 | 15.0 | 13.0 x 42.8 | 18.7 x 49.0 |
| Rectangle End Cap | 20x60mm | Black | 1.5–3.0 | 60x20mm | 5.0 | 14.0 | 14.0 x 54.0 | 18.2 x 58.0 |
| Rectangle End Cap | 20x70mm | Black | 1.0–3.0 | 70x20mm | 5.0 | 19.3 | 13.1 x 62.3 | 18.4 x 67.5 |
| Rectangle End Cap | 20x80mm | Black | 1.5–3.0 | 80x20mm | 5.0 | 17.5 | 12.9 x 74.3 | 18.0 x 78.4 |
| Rectangle End Cap | 20x100mm | Black | 1.5–3.0 | 100x20mm | 5.0 | 16.9 | 12.1 x 92.4 | 18.0 x 98.3 |
| Rectangle End Cap | 25x30mm | Black | 1.0–2.5 | 30x25mm | 5.0 | 13.6 | 19.6 x 24.5 | 23.1 x 28.5 |
| Rectangle End Cap | 25x35mm | Black | 1.0–2.5 | 35x25mm | 4.6 | 13.5 | 20.0 x 29.5 | 24.3 x 33.7 |
| Rectangle End Cap | 25x40mm | Black Grey White | 1.5–2.5 | 40x25mm | 5.0 | 14.0 | 19.8 x 32.5 | 23.4 x 38.0 |
| Rectangle End Cap | 25x45mm | Black | 1.5–3.0 | 45x25mm | 5.0 | 13.0 | 18.2 x 38.5 | 23.1 x 43.4 |
| Rectangle End Cap | 25x50mm | Black Grey White | 1.5–3.0 | 50x25mm | 5.0 | 16.0 | 15.8 x 40.5 | 22.8 x 47.2 |
| Rectangle End Cap | 25x60mm | Black | 1.5–3.0 | 60x25mm | 5.0 | 16.8 | 17.2 x 52.3 | 23.2 x 58.6 |
| Rectangle End Cap | 25x70mm | Black | 1.5–3.0 | 70x25mm | 5.0 | 16.8 | 17.3 x 62.3 | 23.2 x 67.7 |
| Rectangle End Cap | 25x80mm | Black | 1.5–3.0 | 80x25mm | 5.0 | 16.7 | 17.2 x 72.6 | 22.9 x 78.5 |
| Rectangle End Cap | 25x100mm | Black Grey | 1.5–3.0 | 100x25mm | 5.0 | 17.0 | 17.2 x 92.4 | 23.1 x 98.3 |
| Rectangle End Cap | 27x40mm | Black | 1.5–3.0 | 40x27mm | 5.0 | 14.0 | 19.8 x 32.6 | 25.4 x 38.2 |
| Rectangle End Cap | 30x40mm | Black | 1.5–3.0 | 40x30mm | 5.0 | 14.0 | 21.7 x 32.4 | 28.6 x 37.3 |
| Rectangle End Cap | 30x45mm | Black | 1.5–3.0 | 45x30mm | 5.0 | 14.7 | 22.9 x 37.0 | 29.0 x 42.8 |
| Rectangle End Cap | 30x50mm | Black Grey | 1.5–3.0 | 50x30mm | 5.0 | 16.0 | 22.8 x 42.5 | 27.6 x 47.5 |
| Rectangle End Cap | 30x60mm | Black Grey | 1.5–3.0 | 60x30mm | 5.0 | 16.0 | 22.5 x 52.0 | 27.8 x 58.0 |
| Rectangle End Cap | 30x70mm | Black | 1.5–3.0 | 70x30mm | 5.0 | 18.8 | 20.5 x 58.9 | 27.8 x 66.7 |
| Rectangle End Cap | 30x80mm | Available to order | 1.5–3.0 | 80x30mm | 5.0 | 18.0 | 21.8 x 71.4 | 28.5 x 78.5 |
| Rectangle End Cap | 30x100mm | Black | 1.5–3.0 | 100x30mm | 5.0 | 15.0 | 19.9 x 91.4 | 27.2 x 98.0 |
| Rectangle End Cap | 30x120mm | Available to order | 1.0–2.0 | 120x30mm | 4.7 | 20.1 | 26.5 x 119.8 | 22.2 x 114.9 |
| Rectangle End Cap | 35x40mm | Black | 1.0–3.0 | 40x35mm | 5.0 | 11.5 | 27.2 x 32.3 | 33.8 x 38.8 |
| Rectangle End Cap | 35x45mm | Available to order | 1.0–3.0 | 45x35mm | 5.0 | 11.0 | 26.7 x 36.8 | 33.7 x 43.5 |
| Rectangle End Cap | 35x50mm | Black | 1.5–3.0 | 50x35mm | 5.0 | 15.0 | 26.7 x 41.5 | 32.1 x 47.3 |
| Rectangle End Cap | 35x70mm | Black | 1.5–3.5 | 70x35mm | 5.0 | 19.0 | 24.0 x 58.5 | 32.1 x 67.3 |
| Rectangle End Cap | 40x50mm | Black | 1.5–3.0 | 50x40mm | 5.0 | 18.0 | 31.0 x 41.0 | 37.7 x 47.9 |
| Rectangle End Cap | 40x60mm | Black Grey White | 1.0–3.0 | 60x40mm | 5.0 | 17.0 | 30.8 x 50.5 | 38.2 x 58.2 |
| Rectangle End Cap | 40x70mm | Black | 1.5–3.5 | 70x40mm | 5.0 | 19.0 | 28.6 x 58.3 | 37.3 x 66.5 |
| Rectangle End Cap | 40x80mm | Black Grey White | 1.5–3.0 | 80x40mm | 5.0 | 17.0 | 28.0 x 68.0 | 37.6 x 77.2 |
| Rectangle End Cap | 40x100mm | Black | 1.5–4.0 | 100x40mm | 5.0 | 19.5 | 27.6 x 87.0 | 37.7 x 96.0 |
| Rectangle End Cap | 40x120mm | Black | 1.7–3.0 | 120x40mm | 5.0 | 19.0 | 27.5 x 107.6 | 38.0 x 117.0 |
| Rectangle End Cap | 45x60mm | Black | 1.5–4.0 | 60x45mm | 5.0 | 14.9 | 34.5 x 50.8 | 42.3 x 58.3 |
| Rectangle End Cap | 50x70mm | Black | 1.5–4.0 | 70x50mm | 5.0 | 19.0 | 37.5 x 57.4 | 47.7 x 67.3 |
| Rectangle End Cap | 50x80mm | Black | 2.0–4.0 | 80x50mm | 5.0 | 19.0 | 37.0 x 67.5 | 47.3 x 76.8 |
| Rectangle End Cap | 50x90mm | Black | 2.0–4.0 | 90x50mm | 6.0 | 21.5 | 36.0 x 76.0 | 46.8 x 86.7 |
| Rectangle End Cap | 50x100mm | Black Grey White | 2.0–4.0 | 100x50mm | 5.0 | 20.0 | 39.3 x 90.0 | 46.3 x 95.5 |
| Rectangle End Cap | 50x120mm | Available to order | 2.0–4.0 | 120x50mm | 5.0 | 21.0 | 34.5 x 104.5 | 45.0 x 115.0 |
| Rectangle End Cap | 60x80mm | Black | 1.5–4.0 | 80x60mm | 5.7 | 20.0 | 46.0 x 66.0 | 57.5 x 77.1 |
| Rectangle End Cap | 60x100mm | Black | 1.5–4.0 | 100x60mm | 5.0 | 21.5 | 46.2 x 85.0 | 57.0 x 95.5 |
| Rectangle End Cap | 60x110mm | Available to order | 3.5–5.0 | 110x60mm | 6.0 | 24.5 | 41.8 x 94.0 | 52.6 x 104.1 |
| Rectangle End Cap | 60x120mm | Black Grey | 2.0–4.0 | 120x60mm | 5.8 | 20.0 | 46.0 x 105.6 | 56.5 x 115.5 |
| Rectangle End Cap | 70x90mm | Available to order | 3.0–5.0 | 90x70mm | 6.0 | 21.5 | 53.0 x 74.0 | 63.9 x 84.9 |
| Rectangle End Cap | 70x110mm | Available to order | 3.0–5.0 | 110x70mm | 6.0 | 24.5 | 53.2 x 94.0 | 94.0 x 105.0 |
| Rectangle End Cap | 80x100mm | Black | 2.0–4.0 | 100x80mm | 6.0 | 24.0 | 65.3 x 84.8 | 76.0 x 96.1 |
| Rectangle End Cap | 80x120mm | Black | 1.5–4.0 | 120x80mm | 5.8 | 26.0 | 62.0 x 101.5 | 76.0 x 115.3 |
| Rectangle End Cap | 80x140mm | Available to order | 2.0–4.0 | 140x80mm | 5.8 | 24.0 | 70.0 x 130 | 76.5 x 136.5 |
| Rectangle End Cap | 100x120mm | Available to order | 3.5–6.0 | 120x100mm | 6.0 | 24.0 | 84.2 x 103.8 | 94.1 x 114.3 |
| Rectangle End Cap | 100x150mm | Black | 5.0–8.0 | 150x100mm | 6.0 | 27.0 | 78.4 x 128.5 | 91.8 x 141.0 |
These rectangular tube inserts must not be used as hole plugs in thin sheet metal or thin panels. Their ribs are designed to grip along the inside walls of a rectangular tube or box section. A hole in thin material does not provide enough depth for the ribs to engage properly, so an insert may push into the opening yet remain loose.
Hole plugs have a different retaining design and are used to close holes in sheet metal, furniture, panels and other components, depending on the plug type. For these applications, use a purpose-designed plug suitable for the hole shape, dimensions and material thickness.
Patrick –
Exactly as described and a perfect fit. great product and excellent service.
Verry HAPPY!
Patrick