E-Commerce Mailer Box

Reading the code FEFCO 0421

The 04 series holds the folder-type boxes and trays: usually one-piece, unglued constructions erected by folding the die-cut blank around or under the product. This is the series of trays, folders and mailers that hold their shape by geometry — locking tabs, ears and hinged lids instead of a glued joint.

Within the series, 0421 is the design published as the Self-Locking Tray with Double End Walls and Hinged Lid. The four-digit code carries the full structural intent — specify it to any converter and both sides mean the same construction; only dimensions and board grade remain to be agreed.

This template is catalogue variant 1 of the 0421 construction, with adjusted proportions or construction detail; the FEFCO code identifies the underlying design.

How the case behaves

The base carries two single side walls and two end walls that fold up, fold back on themselves and drop their tabs into slots in the base, locking the tray square. Dust flaps on the side walls fold inside the doubled end walls before they close. The lid continues from the back wall, carries its own side flaps, and closes with a tuck flap that slides into the front wall.

Typical uses

E-commerce mailers and subscription boxes packed by hand, product boxes that double as the shipping pack, and sample kits — the doubled end walls take the knocks in parcel networks.

Dimensions and board

The parameters above — internal length, width and depth, plus any construction-specific values this style needs — drive the whole blank: panel layout, flap depths and slot positions all derive from them, validated against the template's supported range. The 2D dieline and the 3D fold preview regenerate together from the same parametric structure.

A corrugated dieline is a starting point for production, not a substitute for converter judgment: flute profile, board grade and joint style all affect final dimensions and crush behavior. Confirm tolerances and material with your manufacturer before mass production — and erect the structure on screen first, so flap collisions and proportion problems surface before any tooling is ordered.

What is E-Commerce Mailer Box — Self-Locking, Double End Walls with Eared Hinged Lid?

FEFCO 0421 is a self-locking tray with double end walls and a hinged lid: the end walls fold double and lock by tab and slot, dust flaps sit inside them, and the lid hinges from the back wall with a tuck flap into the front. One blank, no glue, which is why it is a standard e-commerce mailer. This template is catalogue variant 1 of the construction.

Which dimensions does the E-Commerce Mailer Box — Self-Locking, Double End Walls with Eared Hinged Lid dieline need?

4 parameters drive the blank: L (length), W (width), D (depth), Corrugated cardboard thickness (mm). Each value is validated against the template's supported range, and the whole dieline regenerates from them.

Can I see how E-Commerce Mailer Box — Self-Locking, Double End Walls with Eared Hinged Lid folds before cutting it?

Yes. The interactive 3D fold preview and the 2D dieline are generated from the same parametric model, so the fold you watch on screen is the geometry of the sheet you cut. Open the template in the studio to fold it at your own dimensions; 3D folding comes with the Workshop and Line plans.