Flat Mailers | Self-Seal & Tab-Lock Shipping Mailers

• Material Composition: White and kraft paperboard flat mailers.
• Size Range: 5 1/8" x 5 1/8" through 20" x 27".
• Pack Quantities: 25-, 50-, 100-, and 200-count case packs.
• Closure Types: Self-seal adhesive and tab-lock closures.
• Configurations: White Stayflats Plus®, standard white flat mailers, and kraft flat mailers.

Flat mailers are rigid paperboard shipping containers designed for documents, photographs, printed materials, certificates, artwork, and other relatively thin items requiring resistance to bending during handling. The section includes white and kraft configurations in sizes ranging from 5 1/8" x 5 1/8" to 20" x 27". Closure options include pressure-sensitive self-seal designs and mechanical tab-lock designs, allowing packaging requirements to be matched to fulfillment procedures. Case quantities range from 25 to 200 mailers depending on size and configuration. White surfaces support labeling and identification, while kraft versions provide an uncoated paperboard exterior for general shipping and storage applications.

Product Comparison Chart

Product Type	Exterior	Closure	Available Size Examples	Case Pack Options
Stayflats Plus® Mailers	White	Self-Seal	5 1/8" x 5 1/8"	200
Self-Seal Flat Mailers	White	Self-Seal Adhesive	6" x 6" to 18" x 24"	25, 50, 100, 200
Tab-Lock Flat Mailers	White	Tab-Lock	9" x 11 1/2" to 17" x 21"	100
Self-Seal Flat Mailers	Kraft	Self-Seal Adhesive	6" x 8" to 13" x 18"	100
Tab-Lock Flat Mailers	Kraft	Tab-Lock	9 3/4" x 12 1/4" to 20" x 27"	50, 100

Configuration Analysis Flat mailers in this section are divided primarily by closure system, exterior finish, size, and case quantity. Self-seal models incorporate an adhesive closure that eliminates the separate application of packaging tape for the primary flap. They are available in white and kraft versions, with listed dimensions ranging from compact 5 1/8" square formats through 18" x 24" formats. Tab-lock mailers use folded locking tabs rather than a pressure-sensitive adhesive as the principal closing method. White tab-lock sizes extend from 9" x 11 1/2" through 17" x 21", while kraft tab-lock configurations extend through 20" x 27". Multiple pack quantities allow the same general mailer format to be matched to different consumption rates.

Material Engineering The listed flat mailers use paperboard construction in white or kraft exterior formats. Paperboard provides greater resistance to folding and creasing than flexible paper envelopes while maintaining a relatively thin shipping profile. The rigid panel structure distributes localized handling forces across a broader surface, which can reduce deformation of documents, prints, photographs, calendars, certificates, and other flat contents. White mailers provide a light-colored exterior suitable for shipping labels, barcodes, routing marks, and handwritten identification. Kraft mailers retain a brown paperboard appearance. Exact board caliper, fiber composition, recycled-content percentage, coatings, and moisture-resistance specifications are not stated in the supplied product list and should therefore be verified at the individual product level when these characteristics affect an application.

Shipping and Handling Standards The supplied product information does not identify UN hazardous-material ratings, DOT hazardous-material certifications, OSHA classifications, or food-contact certifications for these flat mailers. They should therefore be evaluated as general shipping containers rather than assumed to meet regulated hazardous-material packaging requirements. Shipping suitability depends on the dimensions, weight, rigidity, and contents of the completed package as well as the requirements of the selected parcel or postal carrier. Buyers handling regulated, hazardous, temperature-sensitive, or food-contact materials should verify whether an additional certified inner or outer packaging system is required. Dimensional tolerances and carrier-specific machinability rules should also be checked before selecting a mailer for automated shipping programs.

Industrial Applications Flat mailers are used in fulfillment operations where thin products require more rigidity than a conventional envelope provides. Publishing and printing operations can use them for catalogs, proofs, photographs, certificates, manuals, and promotional materials. E-commerce facilities may use smaller sizes for media, collectible items, printed accessories, or other low-profile products. Educational and administrative operations can use larger formats for documents, presentation materials, and records. Art, photography, and design businesses may use rigid mailers for prints and similar flat media. The available range from approximately 5-inch-square formats to 20" x 27" mailers permits packaging selection according to the footprint of the shipped item rather than using oversized cartons.

Selection Criteria Mailer selection should begin with the finished dimensions and thickness of the product. Adequate clearance is needed for insertion without forcing the contents or deforming the mailer. Closure type is another operational factor. Self-seal designs can reduce closure steps in repetitive packing operations, while tab-lock designs use a mechanical folding configuration. Exterior finish may be selected according to identification, presentation, or facility packaging standards. Case quantity should be matched to usage volume and storage capacity; this section includes 25-, 50-, 100-, and 200-count configurations. Buyers should also assess board rigidity, closure security, edge protection, moisture exposure, carrier requirements, and whether additional cushioning or internal sleeves are necessary for abrasion-sensitive contents.