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Postal Lock Mailer - Maxi - 345x245x23mm

Postal Lock Mailer - Maxi - 345x245x23mm

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Excl. Tax: £20.00 Incl. Tax: £24.00


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Internal Dimensions- 345 x 245 x 23mm

Download PDF template
Download the PDF template for this product. We recomend opening this in Adobe illustrator to drop your artwork in. If you have any questions get in Contact

Turnaround Time - Our standard turnaround time is 10-15 working days

Xmas opening hours- Our factory is closed for the Xmas holidays from noon 24th Dec - 2nd Jan.

Feel free to place your orders during this time and get in touch via email.

If you are looking for a pre-christmas delivery - please contact us on 01707 387743 or hello@woohoop.com

Are you looking for a custom design? Our in-house carton design team is happy to help create a bespoke packaging solution.

Bespoke enquiry



Details - Maxi Size Postal Lock Style

Dimensions (mm) Material Print Spec Finishing
345 x 245 x 23mm 900 micron White micro-flute Board CMYK Full colour 1 side Die-cut & Creased

The Maxi Size mailer box is the largest size package that will still fit within the royal mail large letter size limit. Designed for the letterbox and constructed out of a rigid high quality micro fluted board to protect heavier items. Great for delivering your product or other contents in a high impact printed box with the strength of a micro-flute board. The Postal Lock style offers a securely packed & robust mailer that shows off your brand.


Royal Mail Large Letter

These fit through the letterbox and qualify as a Royal Mail Large Letter Format when posted and under 750 grams.

Simple self-assembly

Sent out flat packed - Minimising storage costs and space requirements. Assembled in seconds and ready to fill.

Locking tabs

Two neat die-cut locking tabs have a firm hold and can be re-closed. Without the need for stickers although a tamper evident seal can be a great addition.

Size & Applications

Box size - 345 x 245 x 23mm

The maximum postal sized Standard Mailer box is a thin robust mailer packaging designed for the post. To arrive on your customers doormat with the contents protected. The large size that fits within the post makes this a very flexible box. Once printed this makes a very effected marketing tool that will ensure your brand message is heard.

  • Document Pack- perfect for presenting your pitch letting you delight the customer from when they receive your package. This is comfortably able to hold your A4 brochure and documentation giving a professional finishing touch to your collateral
  • Subscription products - Provides a package for subscription products like T-shirts to be delivered regularly.

If you are looking for a different size our postal sizes (small enough to fit through the letterbox) & our parcel sizes (for larger items) or alternatively submit a custom request and get one our cardboard engineers to create a bespoke size for you

Packaging Material

A Micro-Fluted Packaging Board White Throughout including the flute

900 microns Thickness

Fully Recyclable board all pulp is sourced from well managed and sustainable sources.

Print Quality

Printed in a Full Colour CMYK print to the outside of mailer box with full coverage

High Quality print giving photo quality results.

Why not order 1 prototype copy to see the finished product before ordering in larger volumes?


Die-cut, Creased & Supplied flat ready for assembly.

Artwork Design

Graphic Design Options

Use our Online Design tool

Click "Use our online design tool" above to use the Woohoop online packaging design tool. Design, preview & approve your design as a 3D proof in minutes.

Upload your Artwork

Alternatively you can design your own artwork offline.

First, download our PDF artwork template (Available above) and drop your artwork in using a design tool (we recommend Adobe Illustrator).

Then click "Upload your artwork as a PDF template" above to Upload & Preview your artwork before ordering your packaging online.

Our Design Services

Our expert packaging designers can handle the graphic design for you

Just send us your design brief and any text, image and logo resources and we will provide a quotation for producing print ready files

Our design services

Bespoke Service

If you can't find what you are looking for we can offer completely bespoke design and production services with custom sizes available just get in contact.

Our bespoke packaging options include:

  • Custom Fitments- We can produce a bespoke platform to hold your product
  • Food Grade Printed Packaging - BRC food grade production is available on request with food grade inks and coatings
  • Specialist Materials - With the ability to use UV inline printing we can print to a wide range of paper and boards.
  • Window Patching and custom apertures - We can produce gift packs with window patches in the size and shape you require.