M-F3/6 Capacity Mailer - Expandable Envelopes (220 x 340mm)
220 x 340 mm (flat packed), expands to 256 x 150 x 70 mm.
Short edge opening flatpack cardboard envelope for A5 books, longer documents and magazines, expanding into a capacity mailer with a tamper evident peel & seal closure.
Designed to accommodate Royal Mail's large letter tariff flat packed, or the small parcel tariff when expanded.
M-F3/6 Capacity Mailer - Expandable Envelopes (220 x 340mm) - Sample (1 Unit) is backordered and will ship as soon as it is back in stock.
Return information
Return information
Returns and Refund Policy
Below you will find our returns policy – which is all about YOU.
We want you to be 100% satisfied with any order placed with us. Therefore if you are dissatisfied with your purchase and wish to return an item you may contact us by email at sales@lilpackaging.com within 30 days of your purchase, stating the reason for return*. We will then supply you with a return address and returns number, which is very important because no goods can be returned without a returns number.
*If the correct goods have been sent and you've made a mistake whilst placing the order, we are happy to accept returns for a refund, but you will need to cover delivery costs. All returns must be organised within 30 days of receiving your order. Items must be unused, undamaged and still have their original packaging and labelling attached. Nothing in these conditions affects your statutory rights as a consumer. The credit card or PayPal account used for the purchase will be credited with the original purchase amount (less any delivery charge paid where appropriate).
For made-to-order products (including our 9000 pizza style postal boxes), unfortunately, we cannot accept returns if you have ordered the wrong size or if your product doesn't fit.
Returns on Digitally Printed items
In the unlikely event of your custom packaging arriving damaged, missing items or is of incorrect specification (outside of the print, material specifications and variances as stated on our product descriptions) then please contact our mail happy team on sales@lilpackaging.com who will be more than happy to help you put things right.
As these items are made to order, we can only offer returns if the items you purchased are deemed faulty.
In all instances, if you’re not happy please do give us a call - we will do what we can to help you.
To avoid disappointment, we always advise that you order 1 unit to test out our service before committing to a larger order.
Delivery and Shipping
Delivery and Shipping
So you've either placed your order for packaging from lilpackaging.com, or you're considering it. Naturally you want to know what happens in terms of our packaging delivery terms to you.
Stock Items (All Products Except Made-to-Order 0427 Pizza-Style Boxes)
All products are in stock and available for fast UK delivery, apart from our made-to-order 0427 pizza style boxes (unless clearly stated otherwise).
- We aim to despatch all stock orders within 1 working day, with orders placed before 12:00pm (GMT) typically despatched the same day.
- In most cases, we aim to deliver all stock items within 2–3 working days.
Palletised Orders
Larger orders containing 10+ packs or oversized products may be shipped on a pallet for added protection.
- We aim to deliver all palletised orders across the UK within 2–3 working days.
- Next day pallet delivery can also be accommodated on request where required.
Your order may be delivered on a pallet if:
- Your order contains 10 packs or more
- Your order contains multiple oversized packaging items
- Your order contains part-pallet or pallet quantities
Free UK delivery is available on orders over £175.
Despatch times may vary slightly during peak periods. Please contact us if your order is urgent.
Made-to-Order 0427 Pizza-Style Postal Boxes Only
The only exception to the above despatch times is our made-to-order 0427 pizza-style postal box range. These are manufactured to order and therefore follow different production lead times as listed below.
Guide to Production Lead Times
- Packs totalling up to 200 units — 7 to 10 working days
- Packs totalling 200 to 500 units — 10 to 14 working days
- Pallet quantities (6,000 units) — 20+ working days
- Custom print orders (minimum 6,000 units) — Please contact us
For custom printed orders, we will email your cutter guide/keyline within 2 business hours for artwork setup approval. Standard pricing is based on a 1 colour print. Please contact us for multi-colour print requirements.
Dispatch times may vary during peak period – please contact us if your order is urgent.
Palletised orders
Your order may be delivered on a pallet if:
- Your order contains 10 packs or more
- Your order contains multiple oversize packaging items or packs of our larger products
- Your order contains Part-pallet or Pallet order quantities
- Please allow up to 48hrs for despatch on all palletised orders
Any specific delivery instructions please make a notation in the designated "delivery instructions" box during checkout. Failure to do so may result in additional costs incurred by us for reshipping or holding your order. Please be advised that failure to provide such information, including business closure dates/times, may result in an invoice being issued for these costs.
Christmas 2026 Promotion Terms & Conditions:
The 12% Christmas promotion is valid on all orders placed during the promotional period and ends at 11:59pm on 5 January 2026. The offer excludes 0427 Pizza-Style Boxes. Discount is automatically applied at checkout and cannot be used in conjunction with any other offer. All orders placed during the festive break will be processed and dispatched from 5 January 2026. Standard shipping times apply from the date of dispatch. Lil Packaging reserves the right to amend or withdraw this offer at any time.
The majority of orders are dispatched via DPD unless palletised or international. If sent via DPD, you will be sent an email or text when the goods have been despatched with an allocated delivery slot.
Delivery times (following production) by Country
- UK - 2-3 working days
- Mainland Europe - 4-5 working days
- USA - 7+ working days
- Canada - 8+ working days
At Lil Packaging® we are working on making FREE SHIPPING an option for locations beyond those already available in the UK. But like all good things, it's going to take a little time. Until then, simply use the UPS delivery cost calculator in your shopping basket to help you figure out the delivery charges that will apply to your location, and your prospective order.
We may deliver goods by separate instalments. Each separate instalment shall be invoiced and paid for in accordance with the provisions of the applicable contract. Each instalment delivery will be a separate contract and no cancellation or termination by either party of any one contract relating to an instalment will entitle you to repudiate or cancel any other contract or instalment.
Some deliveries may require TSS codes or EORI numbers. Please read our EORI and TSS guide here.
M-F3/6 Capacity Mailer - Expandable Envelopes (220 x 340mm)
M-F3/6 Capacity Mailer - Expandable Envelopes (220 x 340mm) - Sample (1 Unit) is backordered and will ship as soon as it is back in stock.
Description
Description
Tamper-Evident Postal Packaging
Our M-F3/6 cardboard envelope mailer is a mid size option in the Lil "M-Spec" range, purpose built for A5 books, longer documents, and magazines that need more protection than a poly mailer but don't need a full box.
Made from strong corrugated kraft cardboard, the M-F3/6 offers box form rigidity in a slim, letterbox friendly format. Pre folded flaps and ghost creases mean fast, consistent packing every time, and the peel and seal tear strip closure means you can seal orders without tape.
Designed to accommodate Royal Mail's large letter tariff flat packed (220 x 340mm), or the small parcel tariff when expanded (256 x 150 x 70mm), helping you keep postage costs down whichever way you pack it. (See our guide to large letter tariff savings for the full postage breakdown.)
Our peel and seal closure uses a high tack adhesive that bonds permanently on contact, unlike lower security seals that can be carefully peeled back and reapplied without obvious signs of tampering. Once sealed, our mailers are tamper evident: any attempt to open the parcel in transit leaves a clear, visible mark, giving your customers confidence that what arrives is exactly what was sent.
Ideal for: A5 paperbacks, longer documents, magazines, photo prints, and other small to medium flat or lightly bulky items.
Lil Packaging is Europe's largest independent producer of ecommerce postal packaging. See more of our M-Range Cardboard Mailers.
Product Specification:
- Size: 220 x 340mm (flat pack) / 256 x 150 x 70mm (expanded)
- Material: Corrugated kraft cardboard
- Closure: Peel & seal, tamper evident
- Postal fit: Royal Mail Large Letter (flat) / Small Parcel (expanded)
- Certifications: FSC®, Plastic Free, Zero Carbon
Why choose the M-F3/6:
- 100% recyclable, FSC® certified, plastic free
- Zero Carbon manufacturing (UK made)
- Peel and seal closure, no tape needed
- Reinforced corners reduce in transit damage
Frequently Asked Questions
Frequently Asked Questions
What size items fit in the M-F3/6 envelope?
The M-F3/6 measures 220 x 340mm flat, suiting A5 paperbacks, longer documents, magazines, and similar small to medium flat or slightly bulky items.
Does the M-F3/6 fit Royal Mail's large letter tariff?
Designed to accommodate Royal Mail's large letter tariff flat packed, or the small parcel tariff when expanded to its full packed depth of 256 x 150 x 70mm.
What is the M-F3/6 made from?
Corrugated kraft cardboard, FSC® certified for sustainable sourcing.
How do I seal the M-F3/6 envelope?
It uses a peel and seal tear strip closure, no tape or extra sealing required.
Are Lil Packaging mailers tamper evident?
Yes, our peel and seal adhesive is designed to bond permanently once sealed, so any attempt to reopen the parcel in transit is immediately visible, rather than being resealable without a trace.
Is the M-F3/6 available in bespoke sizes?
Bespoke sizing is available on request, typically with a 5000 unit MOQ, get in touch for custom specifications.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
Why our M-F3/6 Envelope is a Lil special
Learn our envelopes special features
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