Our cardboard envelopes (278mm x 400mm) which are gusseted to offer the flexibility of a small postal box when goods are inserted. Suitable for books, magazines, DVD's CD's, Blu-ray disks, gaming disks, diaries, hard backed books and other similar sized items. Our solid board cardboard mailers are rigid to offer protection of goods whilst in transit. They come with an easy peel and 'super' strong adhesive seal for simple and secure closure with a customer friendly ripper strip. These cardboard book wallets are also available for bulk buy should you need larger quantities for e-commerce. Our cardboard mailers are brown in colour and fully compatible with Royal Mail's Small Parcel category.

Our standard solid board cardboard book mailers are manufactured with light to medium duty, 400gsm solid cardboard. They are envelope-shaped and offer perfect protection for a range of different products. Our solid board 278x400mm envelopes are manufactured from 100% recycled and recyclable cardboard material and ensures high quality protection of your items during transit.

We currently offer two different strengths of cardboard envelopes - Solid Board & Premium Corrugated. When goods are inserted and wrapped in our solid board 278x400mm mailer, it acts like a Small Postal Box. Click here to view the premium corrugated 278x400mm mailer.

Pricing in Proportion (PiP) sizes

All of our cardboard envelopes & mailers can be identified using Royal Mail’s Pricing in Proportion index. These Solid Board Cardboard Envelopes (278mm x 400mm) specifically fall into the 'Small Parcel' category.

Product Features of our Solid Board Cardboard Envelopes & Mailers - 278mm x 400mm

• Envelope-like mailers manufactured from 100% recycled and recyclable material.
• Closure - All cardboard envelopes have a peel and seal strip, for easy and secure closure.
• Strength - solid board with 400gsm solid board. Designed for light to medium duty.

Product Details

• Scored for increased capacity – up to 40mm.
• Colour - Brown / Manila.
• Flat Dimensions (W x L) - 278x400mm / 27.8x40cm.
• Load Dimensions (W x L x H) - 238x360x40mm / 23.8x36x4cm.
• PiP Size When Flat - Small Parcel.
• PiP Size When Expanded - Small Parcel.
• For size guidance only this would replace the Kite Packaging code - CSB238X40X360.
• Parcelsend UK SKU - SB-CE278, MCP-SB-CE278-PSUK & MCP-SB-CE278.

Due to manufacturer tolerances, actual item dimensions may vary by 10–20mm. If precise sizing is important for your project, we strongly recommend requesting a sample before placing your order.

All of our products are manufactured and dispatched right here in our own UK warehouse, which means we can offer some of the fastest turnaround times in the country. And because everything is produced in the UK (unlike many other providers), you’ll never have to worry about customs delays or surprise charges. Delivery is calculated at checkout based on order value - free over £100, from £6.95 under that or select Next Day delivery upgrade for only £9.95. All orders are shipped flat-packed for maximum efficiency.