Cross-Brand Modular Box Compatibility

"Compatible" gets used for four completely different situations in this category, and the difference decides whether a stack is safe to pick up by the bottom box. Before any matrix is useful, the word needs splitting.

Four meanings of compatible

Most published compatibility advice conflates the first two. A stack that indexes will travel fine on a flat van floor and separate the moment you tip it onto a hand truck.

The footprint families, with verified numbers

There are four significant plan formats in the western market plus several one-brand outliers.

Note also that "400 x 300" is itself nominal shorthand. The real systainer number is 396 x 296 mm, and the Tanos catalogue publishes heights without feet, adding 7 mm for M, L and XXL bodies and 5 mm for S. That is why a SYS3 M 137 measures 130 mm in the table and 137 mm on the shelf. If you are cutting shelving to fit, use the with-feet number.

Latch geometry, which is what actually decides compatibility

Two boxes can match on plan dimensions and still be incompatible, because the joint lives in the vertical features, not the outline.

• Rotary central controller (T-LOC). One handle on the front face. Rotating it both locks the lid and links the box to the one below. Systainer3 and Systainer T-LOC use this. Because the mechanism is central and the mating features are the body feet indexing into lid recesses, any licensed systainer-format box works with any other, across brands and across generations.
• Corner clips. The 1993 Classic-Line used four joining clips at the corners. Classic boxes still connect to later generations because the footprint and lid geometry survived, but the clip is a different action from the T-LOC turn.
• Sprung side latches that auto-engage. DeWalt ToughSystem 2.0 latches cam over hooks when you press a box down. Bosch's L-BOXX click system is conceptually similar. Both are one-motion, both are brand-specific hook geometry.
• Cleat and channel with manual latches. Milwaukee Packout molds undercut cleats onto the lid and matching channels into the base. You seat the box by sliding it forward, then rotate two side latches over hooks. This is the only major system where horizontal shear and vertical retention are handled by two entirely separate features, explained in full in the Packout system guide.

The practical consequence: a system with a central latch (systainer) can be licensed and copied by other brands cheaply, because the interface is simple and symmetric. A system with asymmetric side hooks (Packout, ToughSystem) is much harder to clone without infringing, which is exactly why those remain single-brand ecosystems.

The compatibility matrix

Read this as "does the row stack onto the column."

Two entries deserve expansion. First, the systainer row is the only genuinely cross-brand "interlocks" cell in the table, and it is the strongest argument for that format if you buy tools from more than one European brand. Second, DeWalt's DWST08017 is the only first-party cross-platform adapter any major manufacturer sells for its own two systems, which tells you something about how seriously the industry treats bridging. The rest of that platform's behavior, including its backwards compatibility with original ToughSystem, is covered in the ToughSystem 2.0 guide.

Riser plates, adapter plates and mounting plates

Three different products get called adapters. They solve different problems.

Mounting plates present one system's coupling features on the top face and mounting holes on the bottom. Milwaukee's Packout Mounting Plate is the archetype: 23.4 x 18.4 x 1.1 in, metal-reinforced fastener holes on 16 in (406 mm) centers, published at 100 lb floor mounted and 50 lb wall mounted. This is not a cross-brand device, but it is the correct way to marry a proprietary system to a generic rack, a van wall or a bench.

System-to-system adapter plates present two different coupling patterns on the two faces. DeWalt's DWST08017 is the significant first-party example inside one brand. Metabo publishes a metaBOX multi-adapter plate whose entire reason for existing is that the systainer grid and the L-BOXX grid do not meet. Beyond those, third-party plates bridge systainer and L-BOXX, and various small manufacturers sell plates that put Packout cleats on one face and a flat bolt pattern on the other.

Risers are single-system spacers that add stack height, usually to clear a wheel arch or to raise a lid above a rail. They do not change compatibility, but they add a joint, which matters for the same reason adapters do.

3D printed and aftermarket adapters

Printed adapters are the most common way people bridge systems today, and they are fine within limits.

Where they work: light organizers, accessory cases, battery holders, hooks, small parts bins, anything under a few pounds that sits at the top of a stack in a shop.

Where they do not: any joint carrying a loaded box, anything in a vehicle, anything that sees repeated impact. Printed parts are anisotropic. A hook printed with layer lines perpendicular to the load will shear along a layer boundary at a fraction of the strength the same geometry would have in injection-molded copolymer. There is no published rating, no batch consistency, and no way to inspect the failure surface before it happens.

A reasonable middle path is to use printed parts for indexing and mechanical fasteners for retention. Print a locator that keeps a box from sliding, then hold the box down with a strap or a bolt. The plastic locates; the metal carries.

The practical rule for one cart or one van rack

You will end up with more than one system. Almost everyone does, because tools arrive in whatever case the manufacturer chose. The rule that keeps that manageable is about columns, not boxes.

1. One latching family per vertical column. Build each column out of a single system so every joint in it is a designed joint with a published rating. Mixing systems within a column is where stacks come apart.
2. Bridge between columns horizontally, not vertically. Put the second system in its own column beside the first, on the same cart or shelf, rather than on top of it.
3. Bolt, do not stack, at the vehicle interface. In a van, the connection to the structure should be a fastener through a mounting plate into a backed rack, not a stack of coupling joints. Coupling latches are convenience features. They are not crash restraints. The full treatment is in mounting modular boxes in a van.
4. Strap across the top of everything. A single cam strap or ratchet over the whole array converts a set of independent columns into one restrained mass and costs about fifteen dollars.
5. Put the heavy box at the bottom of each column, regardless of which system it belongs to. Center of gravity beats latch rating every time on a rough floor.

Where this leaves each buyer

If you buy from several European brands and want your cases to work together out of the box, the systainer format is the only answer, and it is a genuinely good one. Details of that ecosystem, including the height numbering convention and what the 20 kg and 40 kg ratings mean, are in Systainer3 and the Tanos ecosystem.

If you are already committed to a single North American jobsite brand, cross-compatibility is not available and should not drive the decision. Pick on accessory breadth, capacity and footprint efficiency instead, which is what Packout vs ToughSystem vs Systainer vs the rest is built to do, with the underlying figures normalized in the modular box spec database.

If you are mixing a premium system with a value-tier system to save money, keep them in separate columns and accept that you are running two ecosystems. That is a legitimate strategy, covered in the value tier, but it is not compatibility. It is coexistence, and the difference is a strap.