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Brain Bag

Regular price $210.00
  • Wilderness 525 Ballistic/Cloud 210 Ballistic
  • Mars Red 525 Ballistic/Cloud 210 Ballistic
  • Black 525 Ballistic/Island 210 Ballistic
  • Coyote 525 Ballistic/Cloud 210 Ballistic
  • Constellation 525 Ballistic/Dawn 210 Ballistic
  • Ursa 525 Ballistic/Cloud 210 Ballistic
  • Black 525 Ballistic/Cloud 210 Ballistic
  • Aubergine 525 Ballistic/Island 210 Ballistic
Add Brain Bag Padded Hip Belt: Add a Size of Cache: Add Freudian Slip: Add Snake Charmer:
  • You can expect your TOM BIHN bag to give you years of hard service. Our bags are guaranteed to be free from defects in materials and workmanship for the life of the bag. That means if something goes wrong and it's our fault, we'll fix it at no charge.

    Same with your Skookum Dog gear: it'll give you years of hard service and is guaranteed to be free of defects in materials or workmanship. If something goes wrong and it's our fault, we'll fix it at no charge. If your dog chews something up or otherwise damages it, we'll repair it for a reasonable fee if it is repairable.

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  • Use this link to open a new tab to a regularly updated list of reviews of our bags.
    Or click here to see reviews posted by our Forum community.


bluesign® certified 525 denier 2x2 Ballistic nylon exterior lined with bluesign® certified 210 denier 2x2 Ballistic nylon
Bottom: 1050d high tenacity ballistic nylon
Spacer Mesh back
Edgeless EV50 1/2" / 12mm shoulder straps (EVAZOTE® OEKO-TEX® foam)
PORON® foam handle
Tough Duraflex®, Nexus, and Woojin buckles and related components
#10 YKK coil zippers on main compartment
#8 YKK coil zippers on pockets


Made in USA with fabric from Korea / Japan / U.S.A.
100% finished seams
38 reinforcing bar tacks


Dimensions: 14" (w) x 18.1" (h) x 9.1" (d) / 355 (w) x 460 (h) x 230 (d) mm
525 Ballistic Nylon: 2 lb 15 oz / 1345 grams
Volume: 2200 cubic inches / 36 liters (ASTM Standard Measure)
Removable 1.5" / 38 mm waist strap included
.5" / 12 mm padded and contoured shoulder straps with .75" / 20 mm removable sternum strap
What's included:
1x 8-inch Black Webbing Snaphook/Snaphook Key Strap
1x Black Cord Zipper Pulls w/ Plastic Ends (8 Pack)
1x Sternum Strap Assembly
1x Gatekeeper Waist Strap
Total O-rings: 9 (3 in the back main compartment; 3 in the front main compartment, 1 in the top small pocket, 1 in left side pocket; 1 in right side pocket)
Want to see the specs for all of our bags?


The ultimate on-your-back student or business organizer, the Brain Bag is our Slant-6 of backpacks: it will surprise you with its utility, versatility, and longevity. Long after lesser bags have frayed their seams, blown their zippers, and popped their straps, the Brain Bag will continue to be your faithful companion. 

The Brain Bag consists of two main compartments plus four external pockets. The small top pocket on the front is perfect for a wallet and cell phone and has an inside snaphook for keys. The two vertical front pockets are large enough for water bottles or even a small thermos; inside both of these pockets are pen/pencil organizers. The left pocket has an outside flat mesh pocket for brochures, plane tickets, or even a small U-lock bike lock. Between the pockets are two lash straps for an umbrella or a raincoat, and above these straps is a heavy-duty snaphook so you can attach water bottle, coffee mug, or what-have-you.

In both of the main compartments (on the back panel of each) are two unobtrusive webbing loops (that we call "rail loops") to which you can secure the optional Cache (available in sizes specifically for every Apple laptop and iPad. When you add the Cache, the Brain Bag becomes a "checkpoint-friendly" laptop backpack. Here's how it works: on the back (or bottom, depending how you look at it) of the Cache are two parallel "rails" of 1" wide lightweight nylon webbing which extend from the top to the bottom. Included (and already attached for your convenience) when the Cache is ordered with the Brain Bag are two Gatekeeper Rail Clips: unclip the side that isn't clipped to the Cache, slip it through the webbing loops in the Brain Bag middle compartment, and flip it shut. Slip the Cache inside the Brain Bag, and pull it back out: you'll see that the Gatekeeper Rail Clips ride the rails of the Cache, allowing you to remove your laptop from the Brain Bag entirely while it is still encased in the protective Cache. Doing this at the airport security checkpoint means the X-ray machines (and TSA personnel) will have a clear, unobstructed view of your laptop — allowing you to keep your laptop in the Cache and the whole affair securely held together as one unit. (We think that's much better than having to remove your laptop and dump it in one of those buckets.) Many of us will appreciate this functionality on a daily basis as well: the rail system can be a convenient and quick way to remove one's laptop from the bag.

Side compression straps compress the Brain Bag when it is not full and stabilize the load; you can also tuck a raincoat, hoodie, or yoga mat under these straps. The Brain Bag has a top handle made of 1/2" PORON® foam wrapped in 1050 denier ballistic nylon fabric. And what about the shoulder straps? Conformity is overrated — except, perhaps, when it comes to shoulder straps. The edgelessness of the Brain Bag shoulder straps allows them to more softly conform to your shoulder — we find that this increases comfort. Yet the straps aren’t too soft: the 1/2” thick EVAZOTE® OEKO-TEX® certified foam means the strap is robust enough to carry a heavy load. Removable 3/4" sternum strap and 1-1/2" waist straps are there if you need them but are easy to remove if you don't. The back is made of Spacer mesh and is padded with 3/8", high quality, closed-cell foam.

If the organizer pockets on the front of the Brain Bag just aren't sufficient, or if you need to carry papers, folders, etc. and keep them neat, consider adding the Freudian Slip. One side will protect those papers; the other provides extra organization for pens, business cards, and small electronics or laptop accessories.

Customer Reviews

Based on 2 reviews Write a review

Design Notes

Our Brain Bag was designed in the mid-1990s as a backpack that could carry my padded laptop insert. (It was originally called Lap Dog, and later renamed Brain Cell.) The name Brain Bag comes from my father's "Brain Bag": the oversized briefcase in which he carried his maps and charts when he flew for Pan Am back in the day. My Brain Bag initially came in two versions: Brain Bag and Big Brain Bag. The standard version had one main compartment, and the "Big" version had two. However, in terms of customer demand, the two-compartment version was the hands-down winner, so I ditched the single-compartment version and focused on the double. It was still called "Big Brain Bag" for some time, but the "Big" eventually dropped from use (as there was no "Small" or "Standard" size anymore), and so it was just Brain Bag.

The two main compartments allowed users to segregate their stuff, as well as to choose between carrying their laptop or having their jacket/clothing against their backs. I added side compression straps pretty early on; folks liked to be able to cinch the thing down when it wasn't full, and also to overload it by tucking a sweater or raincoat under the straps.

The pocket design on the front of Brain Bag was conceived as a way to have a reasonable number and variety of easily accessible pockets, but still maintain a relatively svelte exterior. The design of the pockets allowed them to be sewn on with zero exposed fabric edges inside the pockets (having no exposed, raw edges of fabric is pretty much religion here). I added the simple pen/pencil organizers inside the two main pockets after folks thought that'd be a useful thing (though I personally tend to just throw all that little stuff into a pocket higgledy-piggledy). We added more "O"-rings and replaced the leather handle with a Poron®-padded one. We changed the 2" webbing waist belt to a 1-1/2" webbing waist belt (more in scale with the bag, IMHO), and we made the waist belt removable and the sternum strap removable too, as soon as appropriate hardware was available. We added a spacer mesh back panel, and a large snap hook at the base of the top pocket for your umbrella, water bottle or travel mug.

Over the years, though we've tweaked and modified and added features to Brain Bag, its basic form is still unmistakable and somewhat iconic. Keep on truckin’, Brain Bag!
- Tom

want help choosing the right size?

1. Measure Your Laptop

Measure your laptop (or Google its make, model, and the word “dimensions” to find its listed dimensions).
Compare its measurements with the chart to the left (swap the Height and Width when measuring for a Vertical oriented Cache).

Laptop Measurements Diagram

2. Compare Those Measurements To These

Size Interior Width Interior Height Interior Thickness
08A (iPad Mini)7.76" / 197mm5.08" / 129mm0.31-0.78" / 8-20mm
10A (10.5" iPad Pro)9.76" / 248mm6.61" / 168mm0.31-0.78" / 8-20mm
10B (iPad or 9.7" iPad Pro)9.33" / 237mm6.46" / 164mm0.31-0.78" / 8-20mm
12B (2018 12.9" iPad Pro)11.75" / 298mm9.13" / 231mm0.31-0.78" / 8-20mm
13A (13" Macbook Air)12.87" / 327mm8.74" / 222mm0.39-1.00" / 10-25mm
13B (Some 13" PCs)12.56" / 319mm8.03" / 204mm0.39-1.00" / 10-25mm
13C (pre-2017 13" Macbook Pro)12.24" / 311mm8.90" / 226mm0.39-1.00" / 10-25mm
13E (11" Macbook Air)11.89" / 302mm7.44" / 189mm0.39-1.00" / 10-25mm
15C (pre-2017 15" Macbook Pro)14.02" / 356mm9.49" / 241mm0.39-1.00" / 10-25mm

your bag already has great built-in organization. that said, you may want to add these optional organizational accessories to further organize and protect what you carry.

Brain Bag Padded Hip Belt

The Brain Bag Padded Hip Belt allows you to carry some of the weight of a loaded Brain Bag on your hips rather than just your shoulders.


The Cache is a protective laptop or tablet sleeve that's available in many sizes to fit a wide variety of devices.

Freudian Slip

Adds 12 organizational pockets to the Brain Bag, of which there are: four folder pockets (folders/papers fit horizontally or vertically), two mesh pockets for bulky items, an open-top pocket for small electronics or a notebook, three pen slots, and a business card slot.

Guardian Light

Our Guardian DF Lights are rugged, easy to use, and work as either flashing safety beacons or interior bag lights. Made in Canada. Choose Strap-Mount as an exterior bag light and Original Base as an interior bag light (includes a lanyard).

Snake Charmer

A handy organizer pouch with two mesh-sided compartments. Dimensions: 10.5" x 5.5" x 3.5" / 270 x 140 x 90 mm.

Whistle Sternum Strap Half

Our Whistle Sternum Strap Half features a nearly impossible-to-lose whistle integrated into the male (usually the left) half of the sternum strap buckle used on our backpacks and convertible travel bags. The Whistle Sternum Strap Half replaces just one-half of the standard sternum strap included with the Brain Bag.

You can expect your TOM BIHN bag to give you years of hard service. Our bags are guaranteed to be free from defects in materials and workmanship for the life of the bag. That means if something goes wrong and it's our fault, we'll fix it at no charge.

Defects in materials or workmanship are uncommon and are most often evident while your bag is still new. Keep in mind that daypacks and briefcases are often subject to serious wear in everyday use. We often see TOM BIHN bags that are still solid and in use after five, ten, fifteen, even twenty or twenty-five years, with minor repairs needed here or there. But remember: only true love lasts forever.

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