Our cardboard envelopes (278x400mm) are gusseted which enables them to act as a small parcel postal box when larger items are inserted into them. These standard solid board cardboard envelopes are built for light to medium duty use and offer great protection to products contained within.

The 278x400mm standard solid board cardboard envelope is designed for much lighter to medium mailing loads. If you are sending heavier duty items then our premium corrugated cardboard envelopes may be of more use to you. Click here to view our 278x400mm premium corrugated cardboard envelopes / mailers.

Pricing in Proportion (PiP) Sizes

Our cardboard envelopes can be identified using Royal Mail’s Pricing in Proportion index. Our 278x400mm sized cardboard envelope specifically fall into the Royal Mail ‘Small Parcel’ category.

Key features of our 278x400mm standard solid board cardboard mailers

• Our 278x400mm cardboard envelopes adhere to Royal Mail’s PiP guidelines, so you can accurately calculate your postage costs.
• For added strength and protection, our standard solid board cardboard mailers have a strong peel & seal closure.
• Assembling our 278x400mm cardboard envelope is quick and simple for all.
• Scored for increased capacity up to 40mm.
• Made from recyclable material.

Product Details

• Colour: Brown.
• Flat Dimensions (width x length): 278x400mm / 27.8x40cm.
• Load Dimensions (width x length x height): 238x360x40mm / 23.8x36x4cm.
• Pack Sizes: Pack of 10, 25, 50, 75, 100, 200, 300, 500, 1000 & 2000.
• PiP Size When Flat: Small Parcel.
• PiP Size When Expanded: Small Parcel.
• For size guidance only this would replace the Kite Packaging code: CSB238X40X360.
• Mailcoms SKU: MCP-SB-CE278.

All third-party product names, product codes, product SKU’s and company names are trademarks or registered trademarks of their respective holders. Use of these names or codes does not imply any affiliation with or endorsement by the trademark holder and nor does it suggest any reference or comparison to the quality of our goods vs the quality of the goods of the trademark holder.

Due to manufacturer tolerances, actual item dimensions may vary by 1020mm. If precise sizing is important for your project, we strongly recommend requesting a sample before placing your order.