Tamper-Evident Postal Packaging Our M-C0/3 cardboard envelope mailer is the smallest size in the Lil "M-Spec" range, purpose-built for small, flat items that need more protection than a poly mailer but don't need a full box. Made from strong corrugated kraft cardboard, the M-C0/3 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. At 150 x 215mm, the M-C0/3 fits neatly within the Royal Mail large letter tariff when packed flat, helping you keep postage costs down on small item shipments. For bulkier contents, the expandable side gussets allow extra capacity, just note this may take the parcel over the large letter thickness limit, in which case it would ship under the small parcel tariff instead. (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: small books, greetings cards, photographs, small documents, jewellery, and other small 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: Flat-packed 150 x 215mm (Expanded - 130 x 80 x 70mm) 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-C0/3: 100% recyclable, FSC® certified, plastic-free Zero Carbon manufacturing (UK made) Peel-and-seal closure, no tape needed Reinforced corners reduce in-transit damage
