Flex Stack Pack Storage System Review

Flex Stack Pack Storage System

Flex Stack Pack Challenges Tool Storage System Hierarchy

What’s your favorite tool storage system? Packout? TStak? Something else? After looking at what the Flex Stack Pack has to offer, you might just change your mind.

Flex Stack Pack Basic Design


Flex Stack Pack Storage System

The classic stackable tool box system has been around for a long time. Take various box depths with the same length and width, and give them a way to connect the bases and tops. At first glance, that’s what the Flex Stack Pack storage system does. Even at the foundational level, there are worthwhile talking points.

It starts with the boxes themselves. They use a durable tool plastic, similar to other premium stackable systems. The lids feature a gasket to keep water and debris out.

Flex Stack Pack Storage System

Organizer boxes with interior buckets nest into the lid to prevent items from wandering around. The latches hold securely and recess on the back side so they’re not snapping down on your fingers when you close them.

While there are other options to get those premium features, now we start to dive into where the Flex Stack Pack begins to set itself apart.

Auto-Connect Interlocking Stack Security

Auto-Connect Latches

The stacking locks are the easiest we’ve used. To lock one box on top of another, simply set it on the lid and press down once you have them lined up. It’s that easy.

To release a box, push out on the locks until you hear them click. They hold themselves open so you can adjust your grip or grab the handle and carry it away. When you take the top box off, the locks spring back into place, ready to accept its return.

Flex Stack Pack Storage System

In case you’re wondering, Flex’s design does include half-box interlocking. Conveniently enough, the hybrid jobsite fan just so happens to fit that half-box size perfectly. Coincidence? I think not.

Serious Weight Capacity

Looking at the three Flex Stack Pack tool boxes that come as a set, it has a higher weight capacity than others. Combined, it can hold 500 pounds. Milwaukee’s Packout set is rated for 425 pounds and DeWalt’s TStak set holds 470. Other options from Craftsman and Ridgid are under 150 pounds.

What The Flex Stack Pack Storage System Does Differently

Gas Strut Lids

Gas Strut Lids

We have to talk more about the lids. The medium box and rolling box have gas strut lids. Yep, no more holding the lid open with one hand while trying to grab a load with the other and wishing you had a third. Whichever member of the design team pushed for this addition, thank you!

Bonus Storage

Flex Stack Pack Storage System

As far as Flex is concerned, the outside of your tool box is fair game for storage, too. There are several exterior storage accessories you can add and they are legit.

  • Cord Wrap FS1605
  • Level Holder FS1602
  • Side (FS1604-2) and Front (FS1603) Attachment Racks
  • Battery Holders (connect to the Attachment Racks or inside some boxes) FS1601
  • Adjustable Charger Mounts FS1606-2 (interior only)
Accessory Rail

The cord wrap and, level holder are self-explanatory, but I want to spend a little more time on the attachment racks, mainly because they’re a brilliant idea. Tools with belt hooks and rafter hooks hang on them and we love the security that avoids knocking them off the top and not having to bend down to pick up our tools from the ground.

Battery Mount

They’re also compatible with battery holders. In addition to mounting on the outside, they also mount on the insides of the rolling and medium tool boxes. Best of all, they just slide it, so you can store batteries on the mounts inside and then pull the whole mount out and set it on the outside rail while you’re working.

Between holding tools and batteries outside the box, you now have more convenient access to the tools you’re using at a height that beats picking things up from the floor any day of the week.

Flex Stack Pack Case Connection

Flex Stack Pack Storage System Case Connection

In addition to the tool boxes, there are also Flex Stack Pack cases that hold accessory sets. Inside the medium and rolling boxes, the lid has connection points to hold Stack Pack cases.

The connections of these cases are more minimal, and it takes a little getting used to. One side is fixed and the other has a spring-loaded button. Set the fixed side into one slot and then snap the spring-loaded side into the other. Despite the minimalist look of the connection, we find that it holds the cases securely.

There are multiple connection points on the underside of those lids, making any size Stack Pack case compatible.

The same connections to the lid also connect the cases to each other. If you need some extra space, you can pop the cases onto the lid and add another layer to them if you like.

Flex Stack Pack Storage System Pieces

Flex Stack Pack 3-in-1 Set

Rolling Tool Box (FS1101)

Rolling Case
  • 9-inch all-terrain wheels
  • Sturdy telescoping handle
  • Removeable handle helps the box fit in a truck bed with the cover down
  • Gas struts
  • Case-compatible lid
  • 2 x Case-compatible plates on the rear wall
  • Double-sided hanging bin
  • Battery-holder compatible on both sides
  • 19 1/2 x 13-inch opening, 14-inch depth
  • IP65 ingress rating

Medium Tool Box (FS1102)

Medium Tool Box
  • Sturdy top carry handle
  • Gas struts
  • Case-compatible lid
  • Double-sided hanging bin
  • Battery-holder compatible on both sides
  • 19 1/2 x 13-inch opening, 9-inch depth
  • IP65 ingress rating

Suitcase Tool Box (FS1103)

Flex Stack Pack Storage System
  • Sturdy side carry handle
  • 2 x covered bins
  • 2 x uncovered bins
  • Uncovered bins fit onto accessory rails
  • 6 x bin dividers
  • 19 1/2 x 13-inch opening, 5-inch depth
  • IP65 ingress rating

Flex Stack Pack Organizer Boxes

Organizer Box FS1301

Organizer Box
  • Sturdy side carry handle
  • See-through lid
  • 4 x single section bins (removable)
  • 2 x double section bins with one divider (removable)
  • 2 x double section bins with two dividers (removable)
  • Lid nests onto bins to prevent item travel
  • Segmented middle section with two dividers (non-removable)
  • 17 1/2 x 13-inch opening, 3-inch depth
  • IP65 ingress rating

Medium Organizer Box (Half-Size) FS1302

Medium Organizer Box
  • Sturdy side carry handle
  • See-through lid
  • 2 x single section bins (removable)
  • 1 x double section bins with one divider (removable)
  • 1 x double section bins with two dividers (removable)
  • Lid nests onto bins to prevent item travel
  • 13 1/2 x 8-inch opening, 3-inch depth
  • IP65 ingress rating

Small Accessory Cases

Flex Stack Pack Storage System Small Accessory Cases
  • 1-inch PH2 impact bit 20-pack FA101001-20
  • 2-inch PH2 impact bit 20-pack FA101002-20
  • 1-inch SQ2 impact bit 20-pack FA101003-20
  • 2-inch SQ2 impact bit 20-pack FA101004-20
  • 1-inch T25 impact bit 20-pack FA101005-20
  • 2-inch T25 impact bit 20-pack FA101006-20
  • 1-inch T30 impact bit 20-pack FA101007-20
  • 2-inch T30 impact bit 20-pack FA101008-20
  • 1-inch Allen and slotted impact bit 20-pack FA101009-20

Medium Accessory Cases

Flex Stack Pack Storage System Medium Cases
  • 45-piece impact bit set FAM10103-45
  • 10-piece carbide-tipped multi-material drill and drive set FAM10601-10
  • 3-piece wood auger bit set FAM10701-3
  • 29-piece driving bit set FAM10101-29
  • 31-piece drill and drive set FAM10001-31
  • 41-piece driving set FAM10102-41

Large Accessory Cases

Socket Set
  • 10-piece thin wall deep well 6-point 1/2-inch drive impact socket set FAM10401-10

Flex Stack Pack Storage System Price

At the moment, the price on the Flex Stack Pack 3-in-1 rolling tool box set looks enticing. Look for it at Lowe’s, Acme Tools, and other Flex retailers for around $299.

The Bottom Line

The deeper we dove into the Flex Stack Pack tool storage system, the more impressed we were. It makes improvements to the basic design of stackable tool boxes, adds premium features you find from other brands, and then takes it to a whole new level with concepts we haven’t seen before. Flex Stack Pack is redefining what you can expect from your toolboxes and everyone else is playing catch up.

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In your review you state the system has a 500 pound load capacity while on Flex website they state 250 pound load capacity, which is correct?


Kenny, Maybe ProToolReviews should give an expected time in stores in their reviews.
Flex Stack Pack are still not in stock in the Central NY state Lowes stores. Although they are finally shipping from Lowes dot com

The Tech Guy

Both being from chervon produced brands, and looking very similar to kobalt casestack, can you tell me if flex boxes and casestack boxes will work together?


This is literally the all in one stack system. Ever since the packout came out, users have been modding the modular system to meet their needs, but there’s nothing more satisfying when a company gives you all the accessories to add on top of the existing. Flex takes it from every brand including the Toughbuilt system.

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