Bubble Wrap Shop Premium Capacity Mailers | Expandable Rigid Cardboard Envelopes | Size Adjustable Amazon Style Box Mailer Mailing Bags for Ecommerce Shipping (10, M4 Mailer 324×386 mm)

• FULL RANGE OF VARIATIONS (M1 TO M4): Available in 4 precision-engineered sizes to accommodate all your shipping needs, with flat profiles expanding effortlessly into rigid, 3D box mailers up to 70 mm deep.
• SMART DEPTH EXPANSION (UP TO 70MM): Features advanced, pre-scored side gussets that naturally adapt to the thickness of your items. Seamlessly transitions from a flat cardboard envelope to a spacious 70 mm deep box mailer to securely fit bulky products without stretching or splitting.
• ULTRA-RIGID PUNCTURE PROTECTION: Crafted from heavy-duty, industrial-grade solid kraft paperboard to prevent bending, creasing, or tearing during rough postal transit. Provides maximum corner protection, making it the ideal choice for mailing valuable items like books, catalogues, tablets, and electronics.
• TAMPER-EVIDENT PEEL & SEAL FLAP: Equipped with an aggressive, high-tack pressure-sensitive adhesive strip that seals flush instantly upon contact. Creates a permanent, tamper-evident lock that completely removes the need for expensive packaging tape and speeds up your packing time.
• 100% ECO-FRIENDLY & RECYCLABLE: Fully sustainable, biodegradable, and compostable packaging made from premium natural kraft board. Features minimalist environmental awareness icons printed on the face, allowing you to showcase an eco-conscious brand image to your e-commerce customers.

Our expandable capacity mailers provide structured packaging for e-commerce shipments. Manufactured from rigid solid kraft paperboard, these mailers help protect contents against bending and corner wear during transit. Featuring pre-scored expandable side gussets, the mailers adjust to the depth of the enclosed items up to a maximum loaded profile of 70mm. This adjustable design accommodates a variety of items—including documents, textbooks, apparel, and electronics—without the need for additional void-fill packaging materials. Each mailer is equipped with an integrated self-adhesive peel-and-seal strip for closure and a perforated pull tab for opening. Available Sizes & Dimensions M1 Mailer: Flat Dimensions: 294 x 228 mm | Max Loaded Size: 219 x 155 x 70 mm. Suitable for small electronics, video games, jewelry boxes, and small paperbacks. M2 Mailer: Flat Dimensions: 239 x 325 mm | Max Loaded Size: 250 x 165 x 70 mm. Suitable for A5 diaries, small tablets, standard books, and cosmetics. M3 Mailer: Flat Dimensions: 280 x 356 mm | Max Loaded Size: 282 x 205 x 70 mm. Suitable for standard tablets, novels, clothing, and software boxes. M4 Mailer: Flat Dimensions: 324 x 386 mm | Max Loaded Size: 312 x 250 x 70 mm. Suitable for A4 documents, clothing, textbooks, and larger tablets.