Affiliate Disclosure: This article contains affiliate links. If you make a purchase through these links, we may earn a commission at no additional cost to you.
Tajima’s (TJM Design Co., Ltd.) “SEF System” is a tool box interlocking system designed by Tajima, a brand famous for its tool belts. Three defining features: IP65 dust- and water-resistance, built-in SEF holders, and click-to-connect stacking. Electricians, plumbers, and interior contractors choose it as the tool box they can rely on from day one.
This article covers six products — the SEF Tool Box S / Standard / Carry, the Drawer Box, and the Parts Box — organized by use case. From how to choose each product to how to combine them, everything is covered from a job-site perspective.
メナThe SEF System’s design philosophy — “works solo, connects in multiples” — changes how you manage tools on site. Tajima’s strength is translating the usability of its tool belts directly into a tool box.
What Is the Tajima SEF System? — Features of a Tool Box Made by a Tool Belt Manufacturer
The SEF System is a tool box interlocking platform designed by Tajima (TJM Design Co., Ltd.). The “click-to-connect” feature shared across all products lets you stack and lock boxes together without rope or straps. It prevents load shifting in transit and lets you quickly pull out individual boxes on arrival at the job site.
Every product meets IP65 dust- and water-resistance, protecting tools in rainy or dusty environments. The same “SEF mounting system” used on Tajima’s tool belt series is built into the outside of each box, enabling a storage style where you hang tools from SEF holders on the exterior.
メナ“Click to connect, detach to carry, stay dry in the rain” — those three points are the SEF System’s design philosophy. Tajima’s job-site know-how from years of tool belt manufacturing is compressed into these boxes.
How to Choose the SEF System
Three Tool Box Sizes: S / Standard / Carry
The SEF Tool Box comes in three types: S, Standard, and Carry. The S (TB-TBOXS) is for job sites where you want a compact, lightweight standalone unit. The Standard (TB-TBOX) serves as the main box holding a full set of power tools. The Carry (TB-TBOXC) is for large sites where you need one person to move a heavy tool set. For your first unit, the Standard offers the best balance of versatility.
The Role of the Drawer Box and Parts Box
The Drawer Box (TB-HBOXL2) is suited for “slide-out consumable management.” The Parts Box (TB-PBOX/L) is suited for “thin-profile, at-a-glance parts management.” Combining them with a tool box lets you separate and organize tools from consumables.
Top 6 Tajima SEF System Picks
Tajima SEF Tool Box S TB-TBOXS
メナThe most compact tool box in the SEF Box series. Its internal height of 247 mm is the perfect size to fit a full set of hand tools for an electrician’s day on site. IP65 dust and water resistance shrugs off job-site rain, and it locks onto other units just by setting it down.
| Outer Dimensions | H312×W523×D328mm |
| Inner Dimensions | H247×W450×D265mm |
| Water/Dust Resistance | IP65 compliant |
| Max Load | 50 kg (lid 100 kg) |
| SEF Holders | Built into exterior |
| Accessories | Inner Tray L, 2 name seals |
The SEF Tool Box S is a compact tool box designed and released by Tajima for the SEF Box series. With internal dimensions of H247×W450×D265mm, it is designed to hold a full day’s worth of hand tools (screwdrivers, pliers, tape measure, voltage tester, etc.) for electricians, plumbers, and building finishers on site.
On site, it connects and stacks with a SEF cart or other tool boxes on arrival, then moves as a unit to the work area. IP65-rated dust and water protection keeps tools safe even in rainy or high-dust environments. The lid’s 100 kg load rating also means it doubles as a step stool or work surface.
The product is designed to connect and stack with all SEF System products, and is released as the top unit in a system configuration using the SEF Carry Tool Box (TB-TBOXC) as the cart base. It handles both “compact standalone use” and “top unit of a full system.”
Tajima SEF Tool Box TB-TBOX
メナThe standard model of the SEF series. The H357mm interior fits a power screwdriver body, charger, and hand tool set all in one unit. IP65 handles rain without issue. The 54 SEF holders — an outstanding storage capacity — make the difference on site.
| Outer Dimensions | H421×W523×D328mm |
| Inner Dimensions | H357×W450×D265mm |
| Body Weight | Approx. 5,250 g |
| Water/Dust Resistance | IP65 compliant |
| Max Load | 50 kg (lid 100 kg) |
| SEF Holders | 54 total (interior + exterior) |
The SEF Tool Box is the standard model designed and released by Tajima for the SEF Box series. The H357×W450×D265mm interior is designed as a “day’s tool box” holding a cordless impact driver body, batteries, charger, and hand tool set all in one unit.
With 54 SEF holders inside and out, you can hang frequently used tools upright on the holders. A 2-way handle (single-hand and two-hand grip) accommodates various carrying styles, and IP65 rating protects tools from rain and dust.
As the core unit of the SEF System, it is designed to connect and stack with the SEF Tool Box S (TB-TBOXS), SEF Carry Tool Box (TB-TBOXC), and SEF Drawer Box (TB-HBOXL2), functioning as a “mobile tool station” in multi-unit configuration.
Tajima SEF Carry Tool Box TB-TBOXC
メナThe SEF Carry rolls over bumps on large tyres while hauling your tools. Move up to 100 kg of gear rolling on wheels, then use it as a work platform right there on site. The job-site lifesaver for avoiding heavy lifts.
| Tyres | Large tyres (step-over capable) |
| Max Rolling Load | 100 kg |
| Connectivity | Compatible with all SEF System units |
| Usage | Tool transport, step stool, work surface combined |
| SEF Holders | Built into exterior |
The SEF Carry Tool Box is a wheeled tool box designed and released by Tajima for the SEF Box series. Large tyres capable of rolling over steps let one person wheel up to 100 kg of tool sets, reducing the physical effort of tool transport at large job sites.
On site you roll the fully loaded unit to the work area and use it in place as a step stool or work surface. The SEF System’s interlocking feature means stacking other SEF boxes on top is the standard operating mode, creating a “mobile tool station.”
Designed as the base unit responsible for moving the entire SEF System, it is released as the bottom unit of a system configuration with the SEF Tool Box (TB-TBOX) and SEF Drawer Box (TB-HBOXL2) stacked on top.
Tajima SEF Drawer Box L 2-Stage Set TB-HBOXL2
メナThe drawer format changes how you organize on site. Left-right linked long slide rails let drawers slide out smoothly, and trays can be removed entirely. Upper stage has a waterproof parts case; lower stage is a free tray for large items. The combined 40 kg load capacity gives you confidence.
| Outer Dimensions | H379×W502×D328mm |
| Max Load per Stage | 20 kg (total 40 kg) |
| Lid Load Rating | 100 kg |
| Slide Rails | Left-right linked long slide rails |
| Upper Stage Accessories | Waterproof parts case tray + waterproof parts case M×4 |
| Lower Stage Accessories | Free tray |
The SEF Drawer Box L 2-Stage Set is a drawer-style storage unit designed and released by Tajima for the SEF Box series. It features left-right linked long slide rails; the upper stage comes with a SEF waterproof parts case tray and waterproof parts case M×4. Optimized for organizing small parts, bits, and consumables.
On site, operate the drawers while the unit is stacked and pull out only what you need. Store tools and large parts in the lower free tray, manage consumables in the upper stage — this “two-layer management” directly cuts time on site.
Designed as the middle unit of the SEF System, the standard configuration — SEF Tool Box S stacked on top, SEF Carry Tool Box below — creates a 3-stage system.
Tajima SEF Parts Box TB-PBOX
メナThe SEF Parts Box is the dedicated consumable organizer. Its shallow H95mm interior lines up bits, screws, tacker staples, and wire connectors neatly. Just stack it on the SEF System and your tidiness transforms.
| Inner Dimensions | H95×W450×D270mm |
| Water/Dust Resistance | IP65 compliant |
| SEF Holders | Built into exterior |
| Dividers | Compatible with optional TB-PBOXP |
| Connectivity | Compatible with all SEF System units |
The SEF Parts Box is a shallow parts management unit designed and released by Tajima for the SEF Box series. The shallow H95×W450×D270mm interior is optimized for at-a-glance management of “small but critical consumables” — driver bits, drill bits, tacker staples, wire connectors, and screws.
On site, the standard practice is to place it on top of the SEF System and pull out only the consumables needed before work begins. IP65-rated dust and water resistance protects consumables from rain and dust, and combining it with the optional divider set (TB-PBOXP) lets you create compartments by category.
Designed as the top unit of the SEF System, it is released to stack on top of the SEF Tool Box (TB-TBOX) to keep the full system compact. The role split — “tools in the tool box, consumables in the parts box” — boosts overall system efficiency.
Tajima SEF Parts Box L TB-PBOXL
メナThe Parts Box L’s appeal is its greater depth and capacity over the standard. Beyond just bits, it fits cord reels, tape rolls, and spare batteries too. The 20 kg max load handles heavy consumable loads with ease.
| Water/Dust Resistance | IP65 compliant |
| Max Load | 20 kg |
| SEF Holders | Built into exterior |
| Dividers | Compatible with optional TB-PBOXLP |
| Connectivity | Compatible with all SEF System units |
The SEF Parts Box L is a large-capacity parts management unit designed and released by Tajima for the SEF Box series. Larger than the standard model (TB-PBOX), it handles not just bits but also cord reels, electrical tape, and spare batteries — bulkier consumables that the standard unit cannot accommodate.
IP65-rated dust and water resistance protects consumables in rainy and dusty environments. The 20 kg max load safely holds heavy consumable sets, and combining it with the optional divider set (TB-PBOXLP) lets you create category-based compartments.
Designed for electrical work, interior finishing, and HVAC sites where consumables are numerous, it is released to centralize consumable management in a single unit where the standard Parts Box (TB-PBOX) falls short on capacity.
Frequently Asked Questions About the Tajima SEF System
How do the SEF System boxes connect to each other?
The “click-to-connect” feature means bottom latches engage automatically when you stack boxes. No rope or separate fixtures needed. Release is also one-handed.
What is IP65? How much moisture can it handle on site?
IP65 is an IEC protection rating covering protection against direct water jets from any direction. It will protect the contents against outdoor work in the rain or light washdown. Submersion is not intended.
What is a SEF holder? Is it the same as the SEF on the tool belts?
Yes — it uses the same “SEF mounting system” specification as Tajima’s tool belt series. Tool holders and belt accessories compatible with the SEF holder can be attached to the outside of the tool box for additional storage.
Summary: Transform Job-Site Tool Management with the Tajima SEF System
Summarizing the six products covered here by use case: the SEF Tool Box S (TB-TBOXS) for compact day-pack hand tools; the SEF Tool Box (TB-TBOX) as the main box for a full set of power tools; the SEF Carry Tool Box (TB-TBOXC) as a 100 kg mobile tool station; the SEF Drawer Box L 2-Stage (TB-HBOXL2) for slide-out consumable management; the SEF Parts Box (TB-PBOX) for shallow, at-a-glance consumable organization; and the SEF Parts Box L (TB-PBOXL) for high-volume centralized consumable management.
For your first unit, start with the SEF Tool Box (TB-TBOX) — it has IP65, SEF holders, and click-connect all in one. Tajima, known for tool belts, has translated its field-tested know-how into a tool box. Electricians, plumbers, and interior contractors reach for it on site and think “this is it.”
メナA tool box isn’t just storage — it’s the infrastructure that structures the flow of your work. Choose the SEF System and watch how site movement changes.
Related Articles
- Milwaukee PACKOUT Storage System Full Lineup
- Milwaukee PACKOUT Complete Guide
- Bosch L-BOXX System Guide
SEF Box Dedicated Accessories
Tajima SEF Parts Box Divider Set TB-PBOXP
メナThe TB-PBOXP is a divider set designed and released for the SEF Parts Box. Creating compartments lines up bits, screws, and tacker staples by type, making the morning tool check dramatically faster.
| Compatible Product | TB-PBOX (SEF Parts Box) only |
| Dimensions | H97×W447×D270mm |
| Material | Polypropylene (PP) |
The SEF Parts Box Divider Set (TB-PBOXP) is a dedicated accessory designed and released by Tajima for the SEF Box series. It creates category-based compartments inside the SEF Parts Box (TB-PBOX), designed to line up bits, screws, tacker staples, and wire connectors by type.
On site, being able to instantly confirm “where is which screw” before work starts eliminates search time. Pairing it with TB-PBOX transforms a shallow parts box into “a neatly divided consumable shelf.”
Designed as the finishing accessory that completes the SEF System’s consumable management layer, it is intended to operate as an integrated unit with TB-PBOX.
Tajima SEF Tool Box Inner Tray TB-TBOXIT
メナThe inner tray takes tool box organization to the next level. It solves the problem of tools scattered loose on the bottom in one go. So essential that the SEF Tool Box includes it as a bundled accessory from day one.
| Compatible Products | TB-TBOXS, TB-TBOX |
| Outer Dimensions | H55×W476×D128mm |
| Inner Dimensions | H50×W440×D100mm |
| Weight | Approx. 360 g |
| Load Rating | 3 kg |
The SEF Tool Box Inner Tray (TB-TBOXIT) is a dedicated inner tray designed and released by Tajima for the SEF Box series. At H55×W476×D128mm outer dimensions, it fits inside the SEF Tool Box S (TB-TBOXS) and SEF Tool Box (TB-TBOX) to create a tray layer.
On site, lay frequently used tools — screwdrivers, pliers, tape measure — in the tray and secure them to a specific zone inside the box. With a 3 kg load rating it holds field tools steadily, and the tray can be lifted out and placed on a work surface.
Also supplied as an included accessory (Inner Tray L equivalent) with the SEF Tool Box S/Standard, it is released to serve as a replacement or additional unit for overall SEF System consumable maintenance.
Tajima Tool Box Worktop TB-WT
メナThe worktop reframes the tool box lid as a “work surface.” PVC matting keeps tools from sliding, and even in a cramped site you can set small items down while working. The moment the SEF System becomes a “mobile work station.”
| Compatible Products | SEF Tool Box, SEF Carry Tool Box |
| Outer Dimensions | H60×W485×D328mm |
| Surface Material | PVC non-slip mat |
The Tool Box Worktop (TB-WT) is a work-surface accessory designed and released by Tajima for the SEF Box series. At H60×W485×D328mm outer dimensions, it attaches to the top of the SEF Tool Box lid and is used as a work surface. A PVC mat on the surface keeps tools, bits, and materials from sliding.
On site, it functions as a temporary staging surface for tools placed next to the box. Keeping tools off the ground and clean makes it ideal for precision tool maintenance and temporary assembly of connection parts.
Designed to complete the SEF System as a “mobile work station,” it is released to attach to the SEF Carry Tool Box (TB-TBOXC) so you can move the site and set up a ready-to-work configuration instantly.
Tajima Tool Box Vehicle Mount TB-MT
メナThe vehicle mount turns the SEF System into a tool box “fixed even while moving.” Compatible with 9mm screw diameter, it mounts directly to the bed of a van or kei truck to eliminate load shift during transit.
| Compatible Products | SEF Tool Box, SEF Carry Tool Box |
| Outer Dimensions | H29×W485×D328mm |
| Compatible Screw Diameter | 9 mm |
| Load Rating | 50 kg (mounting surface 20 kg) |
The Tool Box Vehicle Mount (TB-MT) is a vehicle-mounting accessory designed and released by Tajima for the SEF Box series. At H29×W485×D328mm outer dimensions, it is designed to directly fix the SEF Tool Box to the bed of a van, kei truck, or work vehicle.
It eliminates the stress of the tool box shifting in the truck bed during transit to the site. With a 50 kg load rating (20 kg on mounting surface), it securely holds a loaded SEF System and is designed to resist vibration during travel without load shift.
Designed to complete the SEF System as “per-vehicle tool management infrastructure,” it is released to combine with the SEF Carry Tool Box (TB-TBOXC) to achieve a smooth “arrive and start work” site deployment.