Postal Lock Mailer - Large Square - 240x245x23mm

Postal Lock Mailer - Large Square - 240x245x23mm

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Excl. Tax: £16.67 Incl. Tax: £20.00


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Internal Dimensions-
240 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 - Estimated delivery between Mon 8th July - Wed 10th July

We manufacture all our packaging in our dedicated UK factory. If you are looking for a specific or earlier delivery date get in touch.

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 - Large Square Postal Lock Style

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

The Large square size will stand out on the doormat with it's square format . Post ready 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 - 240 x 245 x 23mm

A Large Square Standard Mailer box is a compact yet very robust mailer packaging designed for the post. To arrive on your customers doormat with the contents protected. The distinctive square shape provides a memorable brand message when printed with your custom artwork.

  • Welcome Pack- Give your new members and customers a first class welcome. With a branded box full of all the gear they need to get started.
  • Subscription products - Provides a package for subscription products like T-shirts to be delivered regularly.
  • Snack packs - If you are sending out a selection of sweets or snacks. This box can be filled up and still fit through the letterbox.

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.
Book a call-back with Woohoop Packaging