Custom Ear Lock Mailer Boxes

Board and Construction

E-flute corrugated board is the usual choice for ear lock mailers. It is thin enough to fold crisply and print sharply, yet strong enough to protect most products in the post. For heavier items or boxes travelling without an outer carton, B-flute adds extra cushioning and crush resistance.

Liners can be white, kraft or black. White gives the brightest colours, kraft gives a natural look that pairs well with one-colour print, and black gives metallic foils and white ink the strongest contrast. Many brands combine a kraft outside with a white inside for a printed interior reveal.

Inside, inserts, tissue and printed cards can all be added. A fitted insert keeps products in place and frames the reveal when the lid opens.

Ear lock boxes can also include a tear strip across the front for a one-time opening, which some subscription brands prefer as a sign the box has not been tampered with. The ears then hold the box closed again if the customer wants to keep it.

Sizing Your Mailer

Measure the product or the set as it will be packed, including tissue, shred or inserts. Add a few millimetres to each internal dimension. Remember that ear lock mailers have reinforced walls, so the external size is a little larger than a simple box with the same internal space; we work from your internal measurements and tell you the external size for postage.

Choosing two or three standard sizes for a subscription or online shop keeps ordering and storage simple. If the contents change from month to month, size for the largest typical set and use inserts or tissue to fill gaps.

Check courier and postal size bands before fixing dimensions. A box that fits a large letter or a small parcel band can save a meaningful amount on postage over many orders.

Printing Inside and Out

The outside of the lid is your main branding surface, with the front panel and sides offering space for a tagline, website or social handle. Full colour designs and patterns work well, as do minimal one-colour logos on kraft. For subscription boxes, some brands print a different colour each month on the same design.

Printing inside the lid gives a reveal when the box opens: a welcome message, a pattern, instructions or a prompt to share the unboxing. The ear lock gives a satisfying moment of resistance as the lid opens, so the reveal feels earned.

Matt lamination protects print from scuffing in transit, and spot gloss or foil on the logo adds a premium touch.

For subscription brands, a small panel on the side for the month name or edition sticker keeps one print run useful across many sends. Inside and outside artwork together is set up as double-sided printed mailer boxes from one dieline.

Packing Tips

Fold the side walls in fully before tucking the lid, so the slots line up with the ears. Pack the box, close the lid, tuck the front flap and press the ears into the slots. If the ears do not seat easily, the box may be overfilled; a slightly deeper box or a thinner insert helps.

For boxes sent without an outer carton, a branded tape or sticker seal across the front flap adds security and shows the box has not been opened. A simple instruction card inside can explain how to reopen and reuse the box for returns.

Train packers on the folding order before the first busy day. Once they have folded a few, assembly is quick, but the first attempt can be confusing without a demonstration. The free proof drawn with the fold sequence is worth printing and pinning above the packing bench.

Check the Wall Height Against the Product Before the Ears Are Drawn

The ears on this box only lock if the side walls fold fully, and they only fold fully if the product sits below the wall height, so the measurement to get right is depth. Pack the contents with tissue and any card, measure the height of the packed stack, and add 5 mm; a product that sits proud of the walls pushes the lid up and the ears never seat. Then add 5 mm to length and width. Choose white liners inside if the lid is printed, kraft outside if parcels take a battering. Say whether a tear strip is wanted, as it changes the lid. Monthly boxes that change artwork keep the same dieline on the subscription mailer boxes for monthly sends.

Email the internal size, board, print inside and out, inserts and quantity, and a custom quote comes back within one working day, followed by a free design proof showing the ears and slots. Mailers are made in 4 to 7 working days once approved and delivered flat, free and tracked, on the UK mainland in 2 to 3 days. Boxes that arrive crushed or misprinted are reprinted or refunded when reported within 10 days.