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Tajima’s (TJMDesign Corp.) ‘SEF System’ is a tool box stacking system designed by the brand renowned for tool belts. Three defining features: IP65 dust/water resistance, built-in SEF holder compatibility, and drop-and-click interlocking. Electricians, plumbers, and interior tradespeople choose it as their straightforward first tool box.
This article covers all 6 products — SEF Toolbox S, Standard, Carry, Drawer Box, and Parts Box — organized by use case. Includes selection guidance and combination tips from a jobsite perspective.
メナThe SEF System’s design philosophy — ‘works standalone, links when you add more’ — transforms on-site tool management. Tajima’s strength is applying tool belt ergonomics directly to tool boxes.
What Is the Tajima SEF System? — Tool Boxes Built by a Tool Belt Manufacturer
The SEF System is the tool-box interlocking platform designed by Tajima (TJMDesign Corp.). The “drop-and-click Stacking Feature” shared across all products lets you stack boxes without rope or separate fasteners. Load shift during transit is eliminated, and at the job site you can pull each box out in seconds.
All products feature IP65 dust and water resistance, protecting tools in rainy or dusty conditions. The same ‘SEF attachment system’ used in Tajima’s tool belt line is built into the exterior, allowing tools to be hung outside using SEF holders — just like on a tool belt.
メナ‘Stack and lock, pick up and go, protected from rain’ — these three points define the SEF System. Tajima’s jobsite expertise as a tool belt maker is concentrated in every product.
How to Choose the Right SEF System Product
3 Toolbox Types: S / Standard / Carry — How to Use Each
The SEF Toolbox comes in 3 types: S, Standard, and Carry. S (TB-TBOXS): lightweight and compact for solo use. Standard (TB-TBOX): the main box for a full power tool set. Carry (TB-TBOXC): for large sites where one person needs to haul a heavy tool set. For a first purchase, the Standard offers the best balance.
The Role of the Drawer Box and Parts Box
The Drawer Box (TB-HBOXL2) is designed for “consumables management via slide-out access.” The Parts Box (TB-PBOX/L) is designed for “slim-profile inventory of small parts at a glance.” Combined with a Toolbox, they let you separate the tools from the consumables.
Top 6 Tajima SEF System Products
Tajima SEF Toolbox S TB-TBOXS
メナThe most compact toolbox in the SEF Box series. The internal depth of H247mm is sized precisely to hold a day’s worth of hand tools for an electrician. IP65 dust/water resistance shrugs off job-site rain, and a simple drop stacks it with any other SEF unit.
| Dimensions (outer) | H312×W523×D328mm |
| Dimensions (inner) | H247×W450×D265mm |
| Water/Dust resistance | IP65 |
| Max load | 50 kg (lid 100 kg) |
| SEF Holders | Exterior mounted |
| Included | Inner tray L · Name labels ×2 |
The SEF Toolbox S is the compact toolbox designed and released by Tajima for the SEF Box series. With internal dimensions of H247×W450×D265mm, it is designed to hold one day’s hand-tool set (screwdrivers, pliers, tape measure, voltage tester, etc.) for electricians, plumbers, and finish carpenters.
On site, it stacks with the SEF cart or other toolboxes on arrival and rolls to the work area. IP65 dust/water resistance keeps tools safe even in rain or high-dust environments. The lid supports 100 kg, designed to double as a step or workbench.
Designed to stack with all SEF System products, it is positioned and sold as the top unit in a system configuration using the SEF Carry Toolbox (TB-TBOXC) as the cart. It handles both “compact standalone use” and “top of a full stack.”
Tajima SEF Toolbox TB-TBOX
メナThe standard model in the SEF series. The H357mm internal depth fits a cordless driver body + charger + full hand-tool set in one box. IP65 handles rain without issue. 54 SEF holders — a remarkably dense capacity that makes a real difference on site.
| Dimensions (outer) | H421×W523×D328mm |
| Dimensions (inner) | H357×W450×D265mm |
| Body weight | Approx. 5,250 g |
| Water/Dust resistance | IP65 |
| Max load | 50 kg (lid 100 kg) |
| SEF Holders | 54 total (inside + outside) |
The SEF Toolbox is the standard model designed and released by Tajima for the SEF Box series. Internal dimensions of H357×W450×D265mm make it a “one-day tool box” designed to hold a cordless impact driver body, batteries, charger, and full hand-tool set.
54 SEF holders inside and out let you hang frequently used tools upright. The 2-way handle (one-hand or two-hand carry) accommodates various grip styles, and IP65 protection shields tools from rain and dust.
As the core SEF System unit, it is designed to link with the SEF Toolbox S (TB-TBOXS), SEF Carry Toolbox (TB-TBOXC), and SEF Drawer Box (TB-HBOXL2) — multiple units together forming a “mobile tool station.”
Tajima SEF Carry Toolbox TB-TBOXC
メナThe SEF Carry rolls tools over steps and uneven ground on large tires. Haul up to 100 kg and use it right on site as a workbench. A site savior that means you never have to lift a heavy tool load by hand.
| Tires | Large (step-traversal capable) |
| Max haul weight | 100 kg |
| Stacking | All SEF System units compatible |
| Uses | Tool transport · step stool · workbench |
| SEF Holders | Exterior mounted |
The SEF Carry Toolbox is a wheeled toolbox designed and released by Tajima for the SEF Box series. Large tires roll over steps while one person hauls up to 100 kg of tools, dramatically reducing manual carrying labor on large job sites.
On site, roll it fully loaded to the work area and use it immediately as a step or workbench. Thanks to the SEF Stacking Feature, the standard configuration is stacking other SEF boxes on top to form a “mobile tool station.”
Designed as the mobility base of the entire SEF System, it is sold as the bottom unit in a configuration where the SEF Toolbox (TB-TBOX) and SEF Drawer Box (TB-HBOXL2) are stacked on top.
Tajima SEF Drawer Box L 2-Tier Set TB-HBOXL2
メナSlide-out drawers change on-site organization. Left-right linked slide rails pull drawers out smoothly, and each tray lifts out entirely. Upper drawer comes with a waterproof parts case; lower drawer is a free tray for large items. Combined 40 kg capacity across both tiers is reassuring.
| Dimensions (outer) | H379×W502×D328mm |
| Max load | 20 kg per tier (40 kg total) |
| Lid load rating | 100 kg |
| Slide rails | Left-right linked long slide rails |
| Upper tier included | Waterproof parts case tray + waterproof parts case M ×4 |
| Lower tier included | Free tray |
The SEF Drawer Box L 2-Tier Set is a slide-out storage unit designed and released by Tajima for the SEF Box series. Left-right linked long slide rails deliver smooth drawer action. The upper tier includes a SEF waterproof parts case tray + waterproof parts case M ×4. Optimized for organizing small parts, bits, and consumables.
On site, operate the drawers while the unit remains stacked — pull only what you need. Storing tool bodies and large parts in the lower free tray and managing consumables in the upper tier creates “two-layer management” that directly cuts on-site search time.
Designed as the middle unit of the SEF System, it is sold as the centerpiece of the standard “3-tier system” — SEF Toolbox S on top, SEF Carry Toolbox on the bottom.
Tajima SEF Parts Box TB-PBOX
メナThe SEF Parts Box is the dedicated consumables organizer. The slim H95mm internal depth lines up bits, screws, staple gun needles, and wire connectors in perfect order. Stack it onto the SEF System and on-site tidiness transforms instantly.
| Dimensions (inner) | H95×W450×D270mm |
| Water/Dust resistance | IP65 |
| SEF Holders | Exterior mounted |
| Dividers | Optional TB-PBOXP compatible |
| Stacking | All SEF System units compatible |
The SEF Parts Box is the slim parts-management unit designed and released by Tajima for the SEF Box series. The shallow internal depth of H95×W450×D270mm is optimized for inventory-at-a-glance management of “small but critical consumables” — driver bits, drill bits, staple needles, wire connectors, and screws.
The standard on-site workflow is placing it at the top of the SEF stack and pulling only the consumables needed before each task. IP65 dust/water resistance protects consumables from rain and dust; the optional divider set (TB-PBOXP) creates category compartments.
Designed as the top unit of the SEF System, it is sold to sit on top of the SEF Toolbox (TB-TBOX) and keep the whole system compact. “Tool bodies in the Toolbox, consumables in the Parts Box” — this role split maximizes system efficiency.
Tajima SEF Parts Box L TB-PBOXL
メナThe Parts Box L offers greater depth and capacity than the standard model. It fits not just bits but also extension cord reels, tape rolls, and spare batteries. Maximum load of 20 kg handles even heavy consumable sets.
| Water/Dust resistance | IP65 |
| Max load | 20 kg |
| SEF Holders | Exterior mounted |
| Dividers | Optional TB-PBOXLP compatible |
| Stacking | All SEF System units compatible |
The SEF Parts Box L is the large-capacity parts-management unit designed and released by Tajima for the SEF Box series. Larger than the standard model (TB-PBOX), it handles bulkier consumables in addition to bits — cord reels, electrical tape, and spare batteries.
IP65 dust/water resistance protects consumables in rain and high-dust environments. The 20 kg max load confidently holds heavy consumable sets, and the optional divider set (TB-PBOXLP) creates compartments by consumable type.
Designed for high-consumable trades — electrical, interior, HVAC — where the standard Parts Box (TB-PBOX) runs short on capacity, this unit centralizes all consumables in a single, larger enclosure.
Frequently Asked Questions about the Tajima SEF System
How do the SEF System tool boxes connect to each other?
The “drop-and-click Stacking Feature” automatically engages bottom latches when you stack the boxes. No rope or separate fasteners required. Release is also one-handed.
What is IP65? How wet can the boxes get on a job site?
IP65 is an IEC ingress-protection rating providing full protection against water jets from any direction. Outdoor work in rain or rinsing with water keeps the tools inside safe. Full submersion is not covered.
What is the SEF Holder? Is it the same as the SEF on tool belts?
Yes — it is the same “SEF attachment system” standard used on Tajima’s tool belt line. SEF-compatible tool holders and pouch parts can be mounted to the exterior of the tool boxes.
Summary: Transform On-Site Tool Management with the Tajima SEF System
A quick breakdown of the 6 products by use case: SEF Toolbox S (TB-TBOXS) — compact one-day hand-tool storage; SEF Toolbox (TB-TBOX) — main box for a full cordless-tool set; SEF Carry Toolbox (TB-TBOXC) — 100 kg mobile station; SEF Drawer Box L 2-Tier (TB-HBOXL2) — slide-out consumables management; SEF Parts Box (TB-PBOX) — slim consumables organizer; SEF Parts Box L (TB-PBOXL) — high-capacity centralized consumables management.
For your first purchase, start with the SEF Toolbox (TB-TBOX) — it combines IP65, SEF Holders, and the Stacking Feature all in one. Tajima’s field-first design philosophy, honed through decades of tool belts, delivers a toolbox that electricians, plumbers, and interior tradespeople immediately recognize as purpose-built for site work.
メナA toolbox isn’t just storage — it’s infrastructure that shapes how work flows. Choose the SEF System and your on-site rhythm changes.
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SEF Box Dedicated Accessories List
Tajima SEF Parts Box Divider Set TB-PBOXP
メナTB-PBOXP is a divider set designed and released for the SEF Parts Box. Adding compartments lets bits, screws, and staples line up by category — the morning tool check becomes 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 partitions the interior of the SEF Parts Box (TB-PBOX) into category compartments, designed to line up small consumables — bits, screws, staple needles, and wire connectors — by type.
On site, “which screw is where” is instantly visible before starting work — search time drops to zero. Combined with the TB-PBOX, the slim parts box becomes a “categorized consumables shelf.”
Designed as the finishing accessory that completes the SEF System’s consumables management layer — a purpose-built add-on intended to be used as one unit with the TB-PBOX.
Tajima SEF Toolbox Inner Tray TB-TBOXIT
メナThe inner tray lifts toolbox organization to the next level. A single tray eliminates the problem of tools sliding around loose on the bottom. Important enough that the SEF Toolbox includes it as a standard accessory from the start.
| Compatible products | TB-TBOXS · TB-TBOX |
| Dimensions (outer) | H55×W476×D128mm |
| Dimensions (inner) | H50×W440×D100mm |
| Weight | Approx. 360 g |
| Load rating | 3 kg |
The SEF Toolbox Inner Tray (TB-TBOXIT) is a dedicated inner tray designed and released by Tajima for the SEF Box series. At H55×W476×D128mm, it is designed to load inside the SEF Toolbox S (TB-TBOXS) or SEF Toolbox (TB-TBOX) to create a tray layer.
On site, arrange frequently used tools — screwdrivers, pliers, tape measure — in the tray and fix them to a specific zone inside the toolbox. The 3 kg load rating holds job-site tools securely, and you can lift the entire tray out and set it on a workbench.
It is also supplied as a standard accessory with the SEF Toolbox S and Standard (equivalent to Inner Tray L), and is sold as a replacement or additional tray to maintain the SEF System.
Tajima Tool Box Worktop TB-WT
メナThe worktop is a conceptual flip — it turns the toolbox lid into a proper work surface. A PVC mat keeps tools from sliding, so you can work on small parts even in tight spaces. The moment the SEF System becomes a “mobile work station.”
| Compatible products | SEF Toolbox · SEF Carry Toolbox |
| Dimensions (outer) | 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, it mounts on top of the SEF Toolbox lid and functions as a work surface. A PVC mat on the surface keeps tools, bits, and parts from sliding.
On site it works as a staging surface for tools next to the toolbox. 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 sold to mount on the SEF Carry Toolbox (TB-TBOXC) so you can move around site and start working immediately.
Tajima Tool Box Vehicle Mount TB-MT
メナThe vehicle mount turns the SEF System into a “tool box that stays fixed while moving.” Compatible with 9mm mounting screws, it bolts directly into van or kei-truck cargo beds and eliminates load shift while driving.
| Compatible products | SEF Toolbox · SEF Carry Toolbox |
| Dimensions (outer) | H29×W485×D328mm |
| Mounting screw diameter | 9mm |
| 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, it is designed to bolt SEF Toolboxes directly into the cargo bed of vans, kei trucks, and work vehicles.
Eliminates the stress of tool boxes shifting in the cargo bed during transit. The 50 kg load rating (20 kg at mount surface) firmly secures a fully loaded SEF System; the design resists load shift even under driving vibration.
Designed to complete the SEF System as “per-vehicle tool management infrastructure,” it is sold to combine with the SEF Carry Toolbox (TB-TBOXC) for seamless “arrive-and-immediately-work” site deployment.