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GWP Packaging

Corrugated cardboard packaging expertise and innovation

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Widest range of protective cases with custom foam in the UK


UK leading independent Correx® packaging manufacturer

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Providing cutting edge ESD safe packaging for 30+ years

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Tri-Mite system

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Tailored to your requirements

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Tri-Mite boxes

If you are looking for a cost-effective, reusable and sustainable alternative to timber cases for your business, Tri-Mite is a great option.

Tri-Mite is a form of triple wall corrugated cardboard with comparable strength to timber. However, It is considerably lighter and can machined to have very precise joints. Tri-Mite containers are stackable, can include a range of fittings and inserts, and can even be painted to any RAL colour. Read more


Plastic free packaging
Biodegradable packaging
Recyclable packaging
PAP 20 corrugated packaging symbol
  • No obligation and no pressure quotes for any packaging.
  • Free and impartial advice from UK based packaging experts.
  • Competitive pricing and full customisation options.
Plastic free packaging
Plastic free
Biodegradable packaging
Recyclable packaging
PAP 20 corrugated packaging symbol

About Tri-Mite heavy duty boxes

The Tri-Mite system, using a form of triple wall corrugated board, provides many benefits.

Firstly, Tri-Mite is incredibly strong and durable. Depending on the size and design of your pack, Tri-Mite can typically withstand over 2.5 tonnes of pressure before starting to deform. This performance means Tri-Mite packs can be easily stacked and provide excellent protection for their contents.

Whilst these properties are similar to regular triple wall material, Tri-Mite also allows for accurately machined joints. Cut at 45 degrees before being taped and glued, it not only provides a very precise and clean appearance but also allows for hinged lids.

Another benefit, in terms of appearance, is that you can choose to have Tri-Mite cases sprayed in any RAL paint colour. You can also add stencilling to provide info on part numbers, handling or safety instructions. It is even possible to coat your Tri-Mite cases with an acrylic coating to provide water-resistant properties.

You can also customise your Tri-Mite boxes with a range of internal fittings. Options include corrugated dividers, custom cradles, and bespoke foam inserts. All these options help prevent damage to your items during transit (and can also make packing and unpacking easier).

Other benefits include being considerably lighter than timber cases (with comparable strength), reusable over many trips, and much easier to recycle than most alternative export or industrial packaging options.

Key benefits of Tri-Mite triple wall boxes

The main features and benefits of Tri-Mite boxes include:

  • Extremely strong – can withstand over 2.5 tonnes of pressure before failure.
  • Triple wall construction and taped joints provide excellent durability.
  • Reusable over many uses/trips.
  • Easily and safely stacked when fully loaded.
  • Lightweight compared to timber to minimise shipping costs and aid handling.
  • Significantly improved appearance compared with traditional heavy-duty boxes.
  • Can be designed to include a hinged lid, aiding packing and unpacking.
  • Additional features, including integral handles and fasteners, improve usability.
  • Optional inserts, including dividers, foam and custom fittings, further improve protection.
  • Can be painted or acrylic coated to enhance lifespan and add water resistance.
  • Can also have printing or stencilled information added to provide instructions.
  • Easily recycled at the end of its usable life.
Recyclable packaging

Recyclable packaging

Tri-Mite boxes are fully recyclable at the end of their usable lifespan.

Packaging with recycled content

Recycled content

Corrugated cardboard typically contains between 50 to 70% recycled material.

Biodegradable packaging


The paper (corrugated) material used in the manufacture of this packaging is biodegradable.

Plastic free packaging

Plastic free packaging

Your Tri-Mite boxes are completely free from plastic materials.

Packaging printed with water-based inks

Water based inks

GWP use water based inks when printing your heavy duty packaging.

Reusable packaging product


The durable nature of Tri-Mite means it can often be reused over multiple trips.

Packaging manufactured in the UK

UK manufactured

GWP manufacture your triple wall boxes in the UK, reducing emissions from transport.

PAP 20 corrugated packaging symbol

Paper/Corrugated cardboard

Tri-Mite boxes use paper-based materials in their construction (corrugated cardboard).

FSC® certified

You can choose to have your Tri-Mite boxes made using FSC certified materials.

What is Tri-Mite?

Tri-Mite is a form of corrugated cardboard, similar to triple wall (it has three layers of fluting). It is similarly strong and durable whilst remaining light in weight. However, unlike triple wall corrugated, Tri-Mite can be machined to create 45-degree angles to make very neat folds/joints.

What are taped joints?

Tri-Mite can be cut with 45-degree angles on its edges, allowing the creation of very neat taped joints (i.e. where the various parts of the box or case join together using tape). This construction gives a clean and precise finish, improving the aesthetics of the packs.

Can I use Tri-Mite instead of timber cases?

Tri Mite is an excellent alternative to timber cases. It can provide comparable strength, is reusable over many trips/uses, and is considerably lighter.

Is Tri-Mite waterproof?

Tri-Mite can be painted or sprayed with an acrylic coating to provide further longevity and resistance to moisture. This option makes it ideal for applications where it may come into contact with water (for example, being unloaded from a vehicle in poor weather or a damp warehouse).

Is Tri-Mite the same as triple wall?

The main difference between Tri-Mite and triple wall cardboard (Triwall) is that Tri-Mite can have angle cuts and taped joints. In contrast, triple wall material is typically converted similarly to standard corrugated (single or double wall). Both, however, provide excellent strength and durability.

Tri-Mite box prices

All of the Tri-Mite packaging that GWP produce is made bespoke to your requirements. You can choose the size, style, optional handles, closures, coatings and more (our design team can recommend the best options for you if unsure). This way, you end up with packaging that is just right for your specific application.

What this does mean, however, is that it is not possible to provide a price before discussing your needs and creating an estimate.

Free quotes and advice

Fortunately, we have a team of packaging experts – designers, engineers, estimators and technical sales staff – all of whom will be happy to create a free, no-obligation quote on any Tri-Mite or other packaging you require.

If this sounds like it would allow you to source your perfect heavy-duty packaging, please contact a member of our team today.

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