Aluminium Tube Black Square - 40 mm x 2 mm (Klemp) - Square aluminium tubes black
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Aluminium Tube Black Square - 40 mm x 2 mm (Klemp) Aluminium Tube Black Square - 40 mm x 2 mm (Klemp) Aluminium Tube Black Square - 40 mm x 2 mm (Klemp)

Aluminium Tube Black Square - 40 mm x 2 mm

Reference: AKZ402

In stock - dispatch in 48h
For every order over €300, we will plant a tree on your behalf. You are still missing €300.00. Read more
€18.03 tax excl.

How to order the target size:

  1. Enter the length (in cm) e.g. 100 cm
  2. Enter the desired quantity, e.g. 4 (now you are ordering 4 100 cm tubes)
  3. Click "Add to basket"
  4. Repeat the steps to order several tube lengths.

If you would like to order pipes longer than 300 cm - please contact us by e-mail. We estimate the transport costs individually depending on the location.

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The essence is in the detail and... simplicity

The idea behind our KLEMP system is to produce fast and hassle-free pipe connections.

The fittings we developed ensure versatility, allowing you to build any structure.

A fastening screw with a hex key socket provides a secure and strong connection to the pipe. Stainless steel screws are also available on request.

Simple solution

Are you dealing with this, too?

Steel and aluminum pipes are commonly used as a structural element, and like all elements, they need to be connected.

What then is the first method that comes to your mind? Welding, right? However, before you opt for this solution....

Explore KLEMP fittings, which allow you to build all kinds of steel and aluminum pipe structures without the need for welding, specialised personnel, professional equipment or long lead times.

Guarantee of efficacy

Extensive offer

The KLEMP fitting system is your partner for the construction of safe balustrades, handrails, railings and many other structures both in industry and for private use. We supply pipes up to 300 cm in length, so making larger structures won't be a problem.


We have up to 600 distinct variants of fittings available. 75 types with 8 different diameters and 3 coating options. Such a wide assortment guarantees that you will find a fitting that is suitable for your structure and that you will complete the construction without using any specialised tools.


KLEMP fittings are TÜV approved, which means you can be sure of their of safety and durability. Also, they are made of hot-dip galvanised cast iron, which makes them highly corrosion- resistant and durable.

Assembly that draws you in

You install and remove KLEMP pipe fittings with an allen wrench.

They are held in place by allen screws. This allows you to implement any design you want, no matter how complex.

Whether you’re dealing with galvanised steel or aluminum pipes – our wide range of pipe fittings means that nearly anything is possible, as long as the right diameter is maintained.

Simple construction and quick assembly also translate to significantly reduced costs of labour.

Why us?

What makes our company stand out is the fact that we have more than 10 years of experience in providing the best pipe and pipe fitting solutions to both individual and business customers.

Our qualified team of experts can advise you on the best solutions. We also provide support for your projects and we are always happy to answer any questions you have.

Data sheet

Size mm
40x40 mm
Aluminium EN AW-6060 T66
Wall thickness
2 mm
0.81 kg/mb
Cut to size
Minimum length
50 mm
Maximum length
6000 mm
Production Standard
EN AW-6060 T66
Average delivery times to Germany and Austria Average delivery times to other European countries Shipping company
Pipe connectors 2 to 3 working days* 3 to 5 working days* DPD / GLS / UPS
Pipes up to 120 cm 3 to 5 working days* 4 to 7 working days* DPD / GLS / UPS
pipes 120-220 cm 4 to 6 working days* 4 to 7 working days* Mainfreight
Pipes 220-300 cm 5 to 7 working days 4 to 7 working days* Mainfreight

* Because it is difficult to estimate the workload in our warehouse and carriers, the delivery time is an estimate. Due to delays in some payment methods, such as bank transfer and instant bank transfer, delivery time may be extended with a few business days. We cannot guarantee the delivery times.

Are you in a hurry? Please contact us. We will see what we can do for you

For over ten years, we have been one of the most reliable partners throughout Germany and Europe when it comes to your projects with pipes and pipe connectors. You will find a comprehensive selection of various steel pipe connectors in our online store, all of which are of course TÜV-certified.

Our pipe connectors have a diameter of 21.3 mm, which are perfect for particularly strong connections with a screw load of six hundred kilograms at a torque of 40Nm. In this case, the pipe connectors are fixed by an Allen screw. In this way, any desired construction, whether sophisticated or rather simple, can be perfectly realized - the possibilities are almost endless, as the selection of different types of pipe connection makes almost anything possible, it does not matter whether you are working with aluminum pipes or galvanized steel pipes, as long as the appropriate diameter is maintained.

Take a look around our site to get a good idea of what is possible with pipe connectors.

Our comprehensive assortment offers not only steel tubes, aluminum tubes and TÜV-approved tube connectors, you will also find a wide range of hooks, clamps and swivels as well as various connectors ( tubeclamps, fittings, etc.) for your project.

We deliver directly to private and business customers through our online store.

If you have any questions or something is unclear, please do not hesitate to contact us.

Corporate clients / B2B clients

Our services are used by large companies known throughout the country and Europe.

We have great logistic capabilities.

We carry out deliveries to companies and offer wholesale prices for larger orders.

We know that as wholesalers and intermediaries you need the lowest prices and special treatment - the fastest possible delivery date and perfect quality.

That is why we have created a special offer for companies to meet these requirements.

Prices and discounts

The shopping cart in the store calculates a quantity discount depending on the number of ordered products.

You can find information about discount thresholds next to each product.

Large orders are negotiated individually (in that case please send your request to our e-mail address).

Invoices and intra-community deliveries

You will always receive an invoice from us for each order.

For business customers there is a possibility to place an order on the basis of a reverse charge. If the order is placed for a German company, for example, the VAT identification number must be provided before the order is placed (by registering the customer account).

The system will then apply a zero VAT rate.

Companies can also order from us on account (after approval) and are entitled to discounts for larger orders.

Deferred payment

Business customers can apply for a credit purchase - an invoice with a deferred payment date. Deferred payment is available only from the second order. The first order must be paid in advance.

Please send us an e-mail. We will then perform a credit and business check.

After the approval it is possible to make a deferred payment (under certain conditions).


Do you need help with your project? Thanks to our extensive knowledge and experience, we are also happy to assist business clients in planning their projects. Would you like to order a custom advertising frame, need pipe racks in your warehouse? We are ready to help you with that.

Would you like to receive a quote for your project? Simply request a quote using the contact form or send an e-mail to


Pipe connectors

About the system

KLEMP pipe couplings are innovative and versatile products for the construction of safe balustrades, handrails, barriers and much more, both in industry and in the private sector. KLEMP couplings allow easy and very fast connection of standard pipes for the construction of modular steel and aluminum structures.
KLEMP couplings are elements that allow extremely flexible implementation of solutions. Despite their simplicity, they are very effective and have proven themselves over the years in thousands of projects all over the world. The KLEMP system safely combines standard sizes of steel and aluminum pipes in almost any layout imaginable, using the widest range of pipe couplings available on the market today.
The couplings are made of hot-dipped galvanized cast iron, giving them high corrosion resistance and long service life.

Why KEMP couplings?

Steel and aluminum pipes have been used as a construction element for many years. They are durable, have no sharp edges and are readily available anywhere in the world. The problem with using steel and aluminum tubing to build various structures is the issue of connections. Threaded pipe must be delivered to the job site in a precisely defined size and offers virtually no flexibility in installation. Welding requires skilled personnel, is a complicated and time-consuming process, and requires specialized equipment.

z systemem KLEMP
Our product for the construction of all types of steel and aluminum pipe structures meets this challenge. Klemp pipe connection system.
Our product range includes different types of galvanized, black and natural connectors.
They are easy to design, easy to install and cost effective due to their modularity and simplicity. The design rules are simple and very effective.



From simple protection of platforms or walkways in workplaces to safe railings in the harsh environment of harbor quays, bridges or canals. The KLEMP pipe connection system offers complete solutions that allow you to carry out such projects.

Private applications

From simple protection of platforms or walkways at workplaces to safe railings in the harsh environment of harbor quays, bridges or canals. The KLEMP pipe connection system offers complete solutions that allow you to carry out such projects.


Inexpensive to assemble. No special skills or tools are required for installation without welding. The couplings are simply plugged onto the pipe and tightened with a hexagonal wrench.
Easy to design and specify, the KLEMP system securely connects standard size pipes together, making any design simple and quick to build.
Wide range of connectors inch tubes. Sketch the railing you want to make, then select the appropriate connectors. Combination couplings allow you to use different sizes of pipe in your designs, which reduces costs while maintaining the required strength.
All couplings have sockets with a set screw that connects the pipe to the coupling. In this way, without welding, we obtain a durable, stable and, above all, safe construction. The advantage of such a combination of elements is the repeatability of strength parameters.
High corrosion resistance, mechanical strength and durability
A flexible system that can be adapted to different conditions
No welding
Unlimited use
A wide range of connectors
Easy and quick assembly
They ensure the repeatability and absolute safety of the connection
Any configuration of the structure
No thread cutting or riveting
It has a TÜV certificate
NLow assembly costs, as personnel without qualifications are sufficient
Low maintenance keeps maintenance costs low


Central to the design principles of the KLEMP system is the principle of realizing a quick and easy connection of pipes. Our connectors provide the versatility to build any design. The KLEMP system consists of cast iron, galvanized connectors. We have developed a wide range of connectors in six different sizes. The hexagon socket clamping screw provides a secure and tight connection to the pipe. Stainless steel screws are available upon request.


KLEMP pipe couplings are easy to assemble and disassemble with an Allen wrench, reusable.

The pipe couplings are fixed with a hexagon socket screw. In this way, any desired design can be perfectly realized, whether it is complex or rather simple - the possibilities are almost unlimited, as the choice of different types of pipe connections means that almost anything is possible, whether you are working with aluminum or galvanized steel pipes, as long as the correct diameter is maintained.

Thanks to the simple design, our connectors allow for very quick assembly, which significantly reduces labor costs.

Product catalog

Discover our complete range of tube fittings and tubes in our exclusive catalog, prepared especially for you. Click on "Download" and you will receive it from us immediately.


Choice of connectors

The connectors shown in the photos are described with dimensions. Each connector has a simple and unique reference code called type to distinguish it from all other connectors. The full code consists of the connector type and size, which indicates the size of the matching pipe or pipes that can be connected.
In our offer you will find connectors for round and square pipes
In our offer you will find square connectors with diameters of 25 mm and 40 mm
In our offer you can find black galvanized connectors and natural connectors without coating.


In our offer you will find round connectors with diameters of 21.3 mm, 26.9 mm, 33.7 mm, 42.4 mm, 48.3 mm, 60.3 mm

* The actual dimension of a connector The clamping screw fixes the pipe with the smaller diameter (tolerance approx. 1.5 mm)
Some KLEMP connectors are approved by TÜV, a leading European and independent testing institute.
We give general guidelines for the use of pipe fittings. However, due to the nature of the product, the ultimate responsibility for the selection and proper use of connectors rests with the customer. The customer should also make sure that the existing structures to which the Klemp couplings will be attached have sufficient load-bearing capacity to support both the Klemp elements and the potential load, taking into account wind forces, snow loads and other superimposed forces.

Why with us?

For more than ten years, we have been one of the most reliable partners in Germany and Europe when it comes to projects involving pipes and pipe fittings. In our online store you will find a wide range of different steel tube fittings.

Through our online store we deliver directly to private and business customers.

If you have any questions or uncertainties, please feel free to contact us.

Our services are used by large companies known throughout the country and Europe. We have great logistic possibilities.


Do you need help with your project? Thanks to our extensive knowledge and experience, we are happy to assist business clients in planning their projects. Do you want to order an advertising rack to order, do you need tubular racks in your warehouse? We are ready to help you with it.

Let us inspire you!

The construction of the hut
Coat hanger
Barbecue counter
Coffee table
Wooden stand
Dining table
Coat hanger

Returns and Exchanges - Stress-Free!

We believe you will be delighted with your purchase, but we understand that sometimes things don't meet expectations. If, for any reason, you want to return a product, we want you to know that it's important to us, and we aim to make it as easy as possible.

You have 14 days to withdraw from the contract without giving any reason. Simply contact us at to inform us of your decision. There's no need to fill out any complicated forms, although a template is available if you prefer to use it.

Note: Please remember that products made specifically to your order, tailored to your dimensions or specifications, are an exception to this rule. Due to their unique nature, we cannot accept returns unless they are defective. We hope you understand that such products are made especially for you and cannot be easily offered to other customers.

We hope that our flexible return policy will make your shopping experience even more pleasant. Thank you for your trust and choosing our shop!

Design efficiently with KLEMP! We offer access to a database of CAD / 3D / STP models of our KLEMP connectors. With the available .stp files, you can easily integrate KLEMP connectors into your engineering projects.

We also encourage you to download our complete product catalog to have a comprehensive overview of our available solutions.

Download CAD Files / 3D / STP Format / Catalog



Select the items you are interested in

Refresh the code


    How are the tubes sized up? (outer diameter)

    Each tube description provides outer tube diameter. In addition, another value provided for a given dimension (e.g. 42x2, 42x3) determines the thickness of the outer wall of the tube. The tube diameter reflects the outer diameter. The associated tubefittings have the same tube diameter in the product name, therefore you always know whether you have the correct size of a connector for your tube. The inner diameter of the fittings is slightly bigger, so you can easily slide them over the tubes.

    Why does the cost of delivery increase when longer product lengths are selected?

    Shipment of oversized loads, i.e. exceeding 120-140 cm, is associated with high transport costs that we incur on the delivery of our products. We sell goods to all EU countries, which in the case of such loads is often associated with a large distance and a non-standard size of the packaging. Weight is another criterion important especially in the case of the purchase of heavier tubes (steel). However, the most important factor affecting the cost of shipping in this case is the length of the load.

    Is it possible to order the tubes in customized dimensions with accuracy to mm?

    No. Due to the already assumed tolerance for cutting (2-3 mm), the adopted length possible to order was rounded to full cm

    To what depth do the tubes go into tubefittings?

    The very depth to which a tube goes in the connector depends on the tube connector used and its diameter.

    The tube usually goes inside the fitting at the depth of at least 2 to 3 cm.

    Usable dimensions can be found in the technical illustration of each tube connector.

    Are the tube diameters provided the inner or outer dimensions?

    The diameter of the tube provided first indicates the outer dimension, followed by the sign "x" after which stands the thickness of the tube wall.

    What is the weight of the tubes?
    The weight of 1 rm of the tube is given for each tube in the Product Specification section.

    Steel tubes are galvanized - what does it mean?

    Our steel tubes are hot-dip galvanized. This means that the steel tubes are coated with a layer of zinc, which makes them resistant to corrosion. The tubefittings are made of cast iron and are fully galvanized. As a result, they are also suitable for external use.

    What is the difference between a steel and aluminum tube?

    Tubes made of steel are stronger and stiffer. For this reason, steel tubes are often used for structures that are exposed to heavy loads and characterized by larger spans. Due to their industrial nature and resistance to scratches, steel tubes are also often used in the manufacture of furniture. Their disadvantage as compared to aluminum tubes is that steel is much heavier. Aluminium tubes are often used for advertising structures. This is to avoid adding up unnecessary load.

    What is the strength of an aluminum tube and a steel tube?

    An aluminum tube, compared to a steel tube, is more susceptible to bending over long intervals. According to our calculations, the maximum distance between two supports (for a wall frame) or two supports (for a freestanding frame) is 150 cm. It is worth noting that steel is much heavier than aluminum. The actual weight per meter can be found in the product description. If you need additional strength calculations, we recommend consulting a constructional engineer or scaffolding specialist.

    Can the tubes be used outdoors?

    All tubes are suitable for external and internal use.

    Galvanized tubes were covered with a protective layer against atmospheric factors using hot-dip galvanizing.

    Aluminium tubes (black) are naturally suitable for external use as they get covered with a protective layer as soon as they come into contact with oxygen.

    Black steel tubes are protected from the weather conditions by a black UV-resistant coating.

    In the course of time corrosion may occur in damaged places and at the edges of the cuts.

    Rust does not affect the strength of the structure and can usually be removed.

    What are the longest tubes I can order with you?

    For galvanized steel tubes and raw aluminum tubes, the maximum length is 600 cm. Black tubes - 300 cm.

    You can order the tubes in maximum length of 300 cm through the shopping cart at our store. If you need longer tubes, please contact us by e-mail.

    Do you cut the tubes to the desired length?

    We cut the tubes to the desired length. Tubes can be cut starting at a length of 5 cm. We do not charge any costs for cutting the tubes. You can select the desired length on the product page and the price will instantly show up.

    What tube diameter do I need?

    The diameter of the tube you need depends on the structure, the span and the weight that the structure is to support. Tables are often made of tubes with a diameter of 42.4 mm. Coat hangers, stair railings, clothes hangers and cabinets have diameters of 26.9 mm and 33.7 mm. For large projects such as canopies and pergolas, diameters of 42.4 mm or 48.3 mm are often used. Click here for a full overview.

    How quickly does the tube get damaged?

    Our tubes are stable and made of durable material. Thanks to their high quality, our tubes are resistant to damage. However, minor scratches may appear on the external surface of the tubes.

    Galvanized steel tubes are resistant to scratches and impacts, and thanks to their sturdy look, any possible scratches will not be noticeable. Aluminum is prone to scratches and can be more easily damaged due to the softness of the material. The black tubes are covered with an impact-resistant coating. Despite the coating, we recommend careful handling of the tubes as the coating is sensitive to scratches, especially with sharp objects.

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