Tamper-Evident Packaging Our M-K7/10 cardboard envelope mailer is the largest size in the Lil "M-Spec" range, purpose built for the biggest documents, prints, and multi item orders that need more protection than a poly mailer but don't need a full box. Made from strong corrugated kraft cardboard, the M-K7/10 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 350 x 470mm flat packed, the M-K7/10's length exceeds Royal Mail's small parcel maximum of 450mm, so flat shipments fall into the standard parcel tariff. Expanded into its box form, it packs down to 386 x 280 x 70mm, comfortably within the small parcel limit, so packing it out can actually bring your shipment into the cheaper small parcel tariff. (See our guide to Royal Mail postage tariffs for the full 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: the largest documents and prints, multi item bulk orders, retail and wholesale multi packs, and other large 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: 350 x 470mm (flat pack) / 386 x 280 x 70mm (expanded) Material: Corrugated kraft cardboard Closure: Peel & seal, tamper evident Postal fit: Royal Mail standard parcel tariff (flat) / Small Parcel tariff (expanded, packs down within limit) Certifications: FSC®, Plastic Free, Zero Carbon Why choose the M-K7/10: 100% recyclable, FSC® certified, plastic free Zero Carbon manufacturing (UK made) Peel and seal closure, no tape needed Reinforced corners reduce in transit damage
