Flat-end cap 40x40x2mm, with tread M8, Satin

The Strofix flat-end cap is an AISI 304 stainless-steel low-profile cap designed to close the open end of the 40 × 40 × 2 mm square railing tube. The cap has a 5 mm height (H) and is supplied in satin finish. Attached using adhesive (elements for pasting included).

The flat-end cap inserts into or sits on the cut end of the 40 × 40 mm square tube, providing a clean, flat closure. The 5 mm height creates a minimal, near-flush profile – unlike domed end caps, the flat cap does not extend visibly beyond the tube face. The 40 × 40 × 2 mm specification matches the Strofix square tube from the Pipes, bars range, ensuring a precise fit. This SKU is a single fixed configuration – there are no selectable finish, grade, or size options. 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:

• Closing the open end of 40 × 40 mm square railing post tubes
• Finishing square post tops where no handrail connection is made
• Providing a flat, flush closure on square tube ends for a minimalist appearance
• Sealing cut square tube ends to prevent moisture ingress in exterior railings
• Completing square tube railing systems with a clean end detail

FAQ:

What tube does this flat-end cap fit?

The flat-end cap fits the 40 × 40 × 2 mm square tube – the standard square railing tube in the Strofix product range. The "40 × 40 × 2" specification refers to 40 mm sides with 2 mm wall thickness.

What is the cap height?

The cap has a 5 mm height (H = 5 mm), creating a flat, near-flush profile on the tube end.

How does this differ from a domed end cap?

A flat-end cap closes the tube with a flat surface at minimal height (5 mm). A domed end cap (such as the ellipsoid caps for Ø42.4 mm tube, H = 24–27 mm) extends significantly beyond the tube face with a rounded profile. Choose the flat cap for a minimalist, flush finish.

How is the flat-end cap attached?

The cap is attached using adhesive (pasting). It inserts into the tube end and is glued in place. Screwing elements are not used.

What steel grade and finish is used?

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

Is this compatible with the Strofix 40 × 40 mm square tube?

Yes. The 40 × 40 × 2 mm specification matches the Strofix square tube exactly, ensuring a precise fit.

About End Caps

An end cap closes the open end of a railing tube, post or crossbar rod, keeping water and dirt out and giving the end a clean, finished look.

Strofix supplies 31 end caps in three families: for Ø42.4 mm tube (flat, convex, ellipsoid, 90° elbow and weld-in caps), for 40 × 40 mm profile (flat and weld-in caps) and for Ø10 and Ø12 mm crossbar rods (15–30 mm high, in flat, ball and droplet shapes).

Most are AISI 304 satin; polished versions, raw weld-in caps and AISI 316 on selected caps complete the range. The correct end cap depends on the profile it closes, the shape and whether it is fitted or welded.