Most fitting returns in the hose trade have nothing to do with quality. The joiner was fine, the hose was fine — they just were not the same size. A connector quoted by its outside diameter gets matched against a hose described by its outside diameter, or a 25mm reducer goes out for a 1" hose that is really 25.4mm, and the job stops at the van door.
For workshops, fabricators, marine engineers and resellers buying fittings by the box, getting the match right once — and building it into how you stock and pick — is worth more than any unit-price saving. This guide sets out the one rule that governs nearly every hose-to-fitting joint, how the couplings range is sized, and how to pick material to suit the duty.
The One Rule: Hose ID Equals Fitting OD
A push-in fitting sits inside the hose, so the measurement that matters on the fitting is its outside diameter, and on the hose it is the inside diameter (bore). A 38mm bore hose takes a 38mm OD joiner. Our couplings are listed by OD for exactly this reason — the aluminium beaded joiner, for example, is sold as OD x ID (38mm x 34.8mm), so the first figure is the one you match to the hose bore. If you need a refresher on how bore and wall relate, see our post on bore, wall thickness and pressure ratings.
Choosing the Fitting Material
What’s in the Range
Figures from the current product pages; prices are per unit at the time of writing — always check the product page for today’s rate and full size list.
| Aluminium Beaded Hose Joiner | 22 sizes from 8mm x 4.8mm to 102mm x 98.8mm (OD x ID), in 50mm, 75mm and 100mm lengths. From £2.30 (50mm long). |
| Aluminium Elbows | 45°, 90°, 135° and 180°, mandrel bent with beaded ends. 17 ODs from 13mm to 102mm. 90° from £5.38. |
| Stainless Steel Elbows | 45° and 90°, T304, 15 ODs from 13mm to 102mm. From £8.55. |
| Aluminium Tube | 1 metre straight lengths, 8mm to 102mm OD, for cutting to suit. 8mm from £3.98. |
| Plastic Hose Joiner | Barbed straight joiner, 25 ODs from 10mm to 102mm, blue, red, black or white. From £0.40. |
| Plastic Reducer & Elbows | Reducers from 12mm–8mm up to 51mm–45mm; 45° and 90° elbows. Reducers from £0.20, elbows from £0.40. |
| T-Pieces | Silicone T-piece (e.g. 25mm x 34mm with 25mm branch, £4.16) and aluminium T-piece (25mm / 25mm, £7.50). |
| Ducting & Pond Joiners | Plastic joiners for polyurethane ducting (from 50mm x 45mm, £3.40) and for corrugated pond hose (19mm to 51mm, from £0.80). |
Matching a Fitting in Five Steps
Stocking Fittings as a Trade Buyer
Fittings are low-value, high-frequency lines: a missing 38mm joiner can hold up a job worth far more than the part. A few habits keep them profitable. Stock fittings in the same bores as your fastest-moving hose so every coil has its connector on the shelf. Use the four plastic colours to code by circuit or customer if you run kits. And add fittings and clamps and clips to your hose order — they all count toward the same £500 minimum (ex VAT), which makes a mixed basket the easiest way to clear it.
Stocked orders dispatch within 1–2 working days of cleared payment, with next-day delivery available and same-day collection from our Mirfield warehouse. Every order is on pro-forma and settled before dispatch — no credit checks and no application stage, which is part of how pricing and stock depth stay where they are. New trade customers take £25 off their first order.
Matching fittings to a hose order? Browse the couplings range, or send the team your bores and duty and we will check the match.
