Overview & Specifications
What Is a Roll End 3 Flap Lock Box?
A roll end 3 flap lock box is a one-piece folding mailer cut from a single die-cut blank, with walls that roll over into a double layer of board and a closure made of three flaps at the front and sides. The flaps fold over the opening in a set order and engage one another, so the box is held shut by the interlock rather than by a single tuck.
How the Three Flaps Lock
The closure works as a short folding sequence.
01
Folding Sequence
The three front and side flaps fold over the opening in the order set on the dieline, each one positioned for the next.
02
Interlock
The flaps engage one another as the sequence completes, so each flap helps hold the others in place rather than one tuck carrying the load.
03
Rolled Walls Underneath
The double-layer rolled walls give the flaps a stiff perimeter to close onto, helping the box hold its shape. Final strength still depends on board, dimensions and packed load.
Anatomy of a Roll End 3 Flap Lock Box
01
Main Closure Flap
Covers the central opening area.
02
Side Locking Flaps
Fold in and engage the main flap.
03
Locking Tabs
Tab and slot details set on the dieline.
04
Rolled Walls
Double-layer perimeter walls.
05
Base
Floor that anchors the walls and flaps.
Each flap shows a different face as it folds, so the outside of the closed box is assembled from several panels. Design across the flap edges so the graphic reads correctly once all three are locked.
What the Closing Sequence Changes
| Factor | Effect of a Three-Flap Closure |
|---|---|
| Hold | Flaps engage one another instead of relying on a single tuck |
| Packing time | More fold steps per box than a tuck lid |
| Opening | A staged reveal as each flap is released |
| Security | Mechanical lock only; not tamper-proof or theft-resistant |
Application guide
When Is a Roll End 3 Flap Lock Box the Right Choice?
A roll end 3 flap lock box suits ecommerce shipments, subscription and sample kits, apparel and accessories, and PR kits where a more involved closing sequence than a single tuck and a staged opening matter more than packing time.
01
More
More Involved Mechanical Closure
Three engaged flaps create a more deliberate closing action than a single tuck-top or tuck-front flap.02
Integrated
Integrated, One-Piece Construction
Walls, base and locking flaps come from one flat blank, with no separate lid to store or match.03
Staged
Staged Opening Sequence
Releasing the flaps one by one turns opening into a short, branded sequence, especially with inside print.04
Alternative
When Another Format May Fit Better
For faster packing with a single tuck, choose the Roll End Tuck Top Box or the Roll End Tuck Front Box. For a lid that lifts off completely, see Roll End Boxes with Lid.
Roll End 3 Flap Lock Box Specifications
Custom roll end 3 flap lock boxes are specified around lock geometry, board and flute, inside dimensions, inserts, print coverage and packed weight, with the three-flap interaction defined on the approved Packaging Dock dieline for each size.
| Specification | Available Configuration |
|---|---|
| Product Type | One-piece roll-end mailer with three-flap locking closure |
| Category | Mailer Boxes |
| Dimensions | Custom inside L × W × D, built around the product, insert and closure geometry |
| Core Construction | Single die-cut blank with double-layer rolled walls |
| Closure | Three interlocking front and side flaps per approved dieline; tape or seal where shipping requires |
| Board | Corrugated (E-flute, B-flute or other flute by project), white SBS, kraft or recycled paperboard; metallic, holographic, pearlescent or textured cardstock |
| Board Thickness (quote form) | Paperboard (18–24 pt), E-flute corrugated, B-flute corrugated, or not sure, advise me |
| Inserts | Paperboard, corrugated, foam/EVA or molded pulp; thermoformed PET/PVC trays also offered for mailers |
| Print Coverage | Exterior only, exterior + interior lid, or full inside and outside |
| Print Methods | Offset, digital, UV, screen or flexographic printing; CMYK and Pantone spot colors |
| Coatings and Finishes | Matte, gloss or soft-touch lamination, aqueous coating, foil stamping, emboss/deboss, Spot UV and raised 3D UV |
| Starting Price | From $1.45 / unit; final price depends on size, board, print coverage, inserts, finishes and quantity |
| Minimum Order | 500 units |
| Standard Production | 7 days from approved proof |
| Rush Production | Available on request |
| Shipping | Ships flat, USA and worldwide |
How 3 Flap Lock Mailers Compare to Other Mailer Structures
All four share rolled walls; the 3 flap lock trades packing speed for a more involved closure.
| Attribute | Roll End 3 Flap Lock | Roll End Tuck Top | Roll End Tuck Front | Roll End with Lid |
|---|---|---|---|---|
| Closure | Three flaps interlock | Single tuck at the top | Single tuck at the front | Separate lid over base |
| Steps to close | Multiple flap steps | Single tuck | Single tuck | Lid placed on |
| Pieces | One | One | One | Two |
| Opening | Staged, flap by flap | Lid swings back | Lid swings back | Lid lifts off |
| Best fit | Deliberate locked opening | Everyday ecommerce | Front-locking presentation | Full-lid reveal |
What Size Roll End 3 Flap Lock Box Do You Need?
Size from the inside out: measure the packed product or insert, add clearance and quote by inside length × width × depth. The three flaps need room to overlap, so flap lengths are set from the inside width and length on the dieline, and packing tests should include the full closing sequence.
How Product Size Becomes Box Size
The figures below are planning references, not fixed manufacturing rules; final allowances depend on product shape, insert, board and flute.
| Step | Typical Allowance |
|---|---|
| Product to inside dimensions | Add about 3–6 mm (1/8–1/4 in) to length and width, 2–5 mm to depth |
| Insert present | Inside dimensions follow the insert's outer size |
| Rolled walls | Outside length and width grow by about four board thicknesses |
| Flap overlap | Set on the dieline so all three flaps engage at the chosen board |
Board and Flute Reference
| Board | Typical Thickness | Typically Suited To |
|---|---|---|
| Paperboard, about 18–24 pt | About 0.45–0.6 mm | Light kits, often inside an outer shipper |
| E-flute corrugated | About 1.1–1.6 mm | Most printed 3 flap lock mailers |
| B-flute corrugated | About 2.5–3.2 mm | Heavier packed weights; flaps stiffer to fold |
Important: These numbers are references, not ratings. Thicker board makes flaps stiffer to fold and lock, so lock fit and board are confirmed together on the dieline and a sample, and no tamper, crush or drop performance is claimed.
If you are unsure, share the product dimensions and weight with the quote request, and the box is sized around them.
Does the Extra Closure Slow Down Packing?
Somewhat. Three fold steps take longer than one tuck, which adds up over large runs. Brands that value the locked, staged opening accept the extra seconds; high-volume fulfillment often chooses a tuck top instead. A packing trial on the sample shows the real time per box.
