BOX USA Stayflat Flat Mailers offer dependable packaging for documents, photos, artwork, and marketing materials. These rigid envelopes are crafted from sturdy chipboard to keep contents flat and secure during shipping and handling. Our stayflat design eliminates bending of contents without the need for extra inserts or stiffeners, ensuring arrival looking professional and undamaged. Each mailer is lightweight, helping to save on postage while still providing excellent rigidity and meet the needs of USPS First Class, Priority Mail, and commercial carrier requirements. These mailers feature a reliable peel-and-seal adhesive strip that makes packing quick, clean, and secure protecting against tampering while providing moisture resistance. For companies managing large order volumes, BOX USA offers bulk packs of 100 or more in multiple sizes making them ideal for e-commerce sellers, fulfillment centers, print shops, and offices that need consistent, professional packaging. Many small businesses use these flat mailers for shipping brochures, photos, invoices, or product literature, while creative professionals rely on them for mailing artwork, proofs, or promotional pieces. The versatile design also makes them suitable for mailing books, magazines, calendars, and other media that must stay flat.