Short answer: Unlike the DeWalt situation covered in this site’s DeWalt storage guide—where TSTAK and ToughSystem are separate lines that need an adapter to bridge—Milwaukee PACKOUT is one unified system. Milwaukee’s own pages consistently state that PACKOUT offers “modular connectivity with ALL PACKOUT components,” which means no adapter is needed between sub-lines because there are no separate sub-lines. The other standout detail: PACKOUT is not just for tools and accessories. Milwaukee also sells dedicated PACKOUT battery racks for both M12 and M18 batteries, and those racks stack directly into the same system as the tool boxes.
One system, not two: what “compatible with all PACKOUT products” means
Where DeWalt splits storage into TSTAK and ToughSystem, Milwaukee organizes everything under PACKOUT. Milwaukee states across PACKOUT product pages that the system offers “modular connectivity with ALL PACKOUT components.” That is not a one-off phrase; it appears consistently on the system’s own pages.
The PACKOUT Tool Box (model 48-22-8424) is described by Milwaukee as “fully compatible with all Milwaukee PACKOUT modular storage products.” It is rated for “up to 75lbs of weight capacity,” with heavy-duty latches, a metal-reinforced locking point, and an IP65 rated weather seal.
Weight capacity depends on the specific product, not the system as a whole
There is no single PACKOUT weight rating. Capacities differ by item, so check the specific product rather than assuming a system-wide number. Milwaukee lists the following figures:
| Product type | Weight capacity |
|---|---|
| Rolling tool box / dolly | 250 lb |
| XL tool box | 100 lb |
| Medium tool box | 75 lb |
| Rack kit, in transit | 50 lb |
Battery racks: PACKOUT bridges to M12 and M18 directly
The most interesting PACKOUT detail is that the system extends to battery storage. Milwaukee sells two PACKOUT battery racks, one per voltage family.
The PACKOUT M18 Battery Rack (model 48-22-8339) is “optimized to store up to four M18 batteries of any size” and, according to Milwaukee, “securely locks onto wall plates, slides onto tool box lids.” The PACKOUT M12 Battery Rack (model 48-22-8338) is built the same way and “stores 4 M12 batteries,” with Milwaukee noting it is “optimized to store up to four M12 batteries of any size.” Both racks also state “modular connectivity with ALL PACKOUT components,” so the racks themselves connect and stack into the broader PACKOUT system, just like the tool boxes.
One clarification worth stating plainly: when Milwaukee says “of any size,” it means any capacity or Ah size within that voltage family. An M12 rack holds any M12 battery; an M18 rack holds any M18 battery. It does not mean M12 and M18 batteries are interchangeable with each other.
Stacking and mounting
Beyond individual boxes and racks, Milwaukee says PACKOUT racks can “stack and expand up to 3 racks high” and can mount multiple kits across a wall. That gives the same wall-mount and stacking logic across tools, accessories, and batteries.
What this guide does not claim
This guide does not claim that M12 and M18 batteries are interchangeable with each other. The phrase “of any size” used by Milwaukee applies to capacity within one voltage family only.
It also does not claim compatibility with any non-Milwaukee storage system. PACKOUT’s compatibility claims are internal to Milwaukee’s own PACKOUT line.
Finally, weight capacity is product-specific, not a single system-wide number. A rolling box, an XL box, a medium box, and a rack kit each have their own rating.
How this was checked
Facts on this page are drawn from Milwaukee’s own PACKOUT storage system landing page, the PACKOUT Tool Box product page, the PACKOUT M18 Battery Rack product page, and the PACKOUT M12 Battery Rack product page.
Sources checked: 2026-08-06. A new review date will only be set after the linked pages are re-checked.