Ultra-Slim & Lightweight Design
Engineered with a 15mm superflat profile, this mailing box minimizes shipping costs while maximizing storage efficiency. Ideal for documents, photos, or lightweight merchandise.

B4 Standard Size Precision (350 x 250 x 15mm)
Perfectly fits B4-sized items like certificates, artwork, or catalogs. Durable white cardboard ensures safe transit and professional presentation.

Reinforced Edge Protection
Heavy-duty construction prevents bending or crushing during shipping. Ideal for fragile items like glass prints, vinyl records, or electronics accessories.

Easy Assembly & Customizable Branding
Pre-scored folds enable quick setup. Blank surface allows custom printing for branding, logos, or promotional messages.

The White Superflat Mailing Box 350x250x15mm B4 Size is the ultimate solution for businesses and individuals needing postal-compliant, eco-friendly packaging for oversized flat items. Designed to meet international large letter standards, its 350x250x15mm dimensions allow cost-effective shipping of B4 documents, posters, art prints, or certificates without triggering oversized parcel fees. Perfect for offices, print shops, and e-commerce sellers, this box ensures your items arrive securely while maximizing postal savings.

Crafted from 2.5mm FSC-certified white corrugated kraft board, this superflat box combines slimline design with industrial-grade durability. Despite its ultra-slim 15mm profile, the reinforced walls withstand up to 10kg/cm² of pressure, safeguarding delicate items like blueprints, vinyl record sleeves, or archival documents during transit. The crisp white finish offers a professional appearance, ready for custom branding, QR codes, or eco-labels to elevate your unboxing experience.

The innovative tape-free assembly system simplifies packaging workflows. Precision die-cut slots and self-locking flaps allow secure sealing in just 5 seconds—no glue or tape required. This feature is ideal for high-volume operations, such as corporate mailouts, print shop orders, or e-commerce fulfillment, reducing labor costs and boosting efficiency.

Sustainability is central to this product. Made from 100% recyclable, bleach-free kraft paper, it supports zero-waste initiatives and plastic-free logistics. Ideal for eco-conscious brands, schools, or businesses aiming to meet ESG goals, this box aligns with global environmental standards while maintaining premium functionality.

Backed by a 2-year quality guarantee, the White Superflat Mailing Box offers flexible bulk-order solutions, including volume discounts and split shipments. Whether you’re a photographer shipping prints, a publisher distributing catalogs, or a startup scaling sustainably, this box delivers reliability, affordability, and eco-responsibility in one sleek design.