Fitting

The Strofix fitting is an AISI 304 stainless-steel inline coupler for 40 × 40 mm square railing tubes. The fitting has a 4 mm height (H) and joins two square tube sections in a straight line. Supplied in satin finish. Attached using adhesive (elements for pasting included).

The fitting is an internal sleeve that bridges the joint between two 40 × 40 mm square tube ends meeting in a straight line. The ultra-thin 4 mm profile means the coupler is nearly invisible once installed — the external surface shows only a minimal seam between the two tube sections. This is used wherever a continuous straight run of square tube railing or handrail exceeds the available tube length and must be extended with a joint. The fitting slides into the bore of both tube ends and is secured with adhesive, creating a rigid, straight connection. AISI 304 stainless steel is suitable for standard interior and exterior installations.

The satin finish provides a uniform appearance that matches other Strofix satin-finished railing components.

Use cases:

• Joining two 40 × 40 mm square tube sections in a straight line
• Extending handrail or top rail runs beyond a single tube length
• Creating a continuous straight square tube railing without visible joints
• Splicing cut tube sections to reach a precise overall length
• Any straight inline connection of 40 × 40 mm square tubes

FAQ:

What tube does this fitting fit?

The fitting fits the 40 × 40 mm square tube — the standard square railing tube in the Strofix product range.

What is the fitting height?

The fitting has a 4 mm height (H = 4 mm). This ultra-thin profile makes the coupler nearly invisible once installed between two tube sections.

Is this a straight or angled connector?

This is a straight inline connector — it joins two tubes in a continuous straight line at 180°. For angled connections, use the flush elbow (90°) or the adjustable flush elbow (90°–180°) for the same 40 × 40 mm square tube.

How is the fitting attached?

The fitting slides into both tube ends and is secured using adhesive (pasting). The Strofix anaerobic glue (50 mL) from the Chemistry, Adhesives subcategory is the recommended adhesive.

How does this differ from the elbows?

The elbows change the direction of the tube run (90° fixed, or 90°–180° adjustable). This fitting maintains the same straight-line direction — it is a splice/coupler, not a direction change.

What steel grade and finish is used?

The fitting is manufactured from AISI 304 stainless steel with a satin finish. AISI 304 is suitable for standard interior and exterior installations.

About Elbows & Connectors

Elbows and connectors are stainless-steel joint fittings that link two sections of handrail or railing tube at a change of direction, creating a continuous, seamless-looking rail line around corners, up staircases and across straight joints. Flush elbows and angles slip over the tube ends and produce a smooth, weld-free joint on the visible surface; welding variants are permanently fused for a rigid connection.

Strofix supplies 15 elbow and connector products for Ø42.4 mm round pipe and 40×40 mm flat square tube, including fixed 90° flush angles, adjustable flush elbows (with one variant covering 0–70°), cross flush angles, tee ("T") connectors, tee corner connectors, inline fittings and welding flush angles — all in AISI 304 stainless steel with a satin finish, with AISI 316 and polished options on selected variants.

The correct fitting depends on tube profile, the angle of the direction change, the number of tube arms meeting at the joint and whether a screwable or welded connection is required.