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Tom Bihn Synapse 25 Backpack Review

The new Tom Bihn Synapse 25 is the larger 25 liter/1526 cubic inch version of the Synapse (now called Synapse 19).  For those familiar with the original pack, the Synapse 25 keeps much of the original design.  The multiple pockets, which don’t cannibalize space from the main compartment, are still there. So is the 1000D Cordura Nylon exterior, 400D Dyneema Riptop interior, water resistant YKK Aquaguard zippers and bulletproof (made in the U.S.A.) build quality.  In essence, Tom has taken everything good about the original Synapse and incorporated it into a larger package with some tweaks to make it even more user friendly.  Let’s take a closer look.

Tom Bihn Synapse 25

Tom Bihn Synapse 25

The Synapse 25 has a clean, sleek design.  There are no snag prone mesh pockets or external pockets which protrude from the main body of the pack.  Much of the complexity of the bag is hidden from view.  It’s also very low profile when empty which helps the wearer resist the urge to fill up the pack with unnecessary gear.

A web strap was added in this version to accommodate a strap mount version of the Guardian Dual Function Light – a safety/utility light that’s built to military specifications  (a great feature for bike commuters).

The Guardian DF Light mounted on the Synapse 25

The Guardian DF Light mounted on the Synapse 25

The EVAZOTE foam shoulder straps and closed cell foam back panel provide for a comfortable carry when the bag is fully loaded.  I’ve typically seen thicker strap padding on a bag this size but, I haven’t experienced any abnormal shoulder/neck pain – even with a laptop, tablet, full Nalgene and other gear in tow.

A removable sternum and waist strap are included although the waist strap is thin and not load bearing.  I removed it shortly after receiving the pack and I didn’t miss it on a pack this size.

The only aspect of the external design I would change on the Synapse 25 is the 1000D Cordura material.  For some reason, it’s a pet hair and lint magnet (I cleaned up the pack prior to taking these pictures).  Not a show stopper, but it left me wishing Tom had opted to use more of the 1050D high tenacity ballistic nylon from the Smart Alec on this bag.


Moving to the interior of the pack, the bottom front pocket is good sized and has three “O-Rings“, for attaching additional accessories via key straps.

I found that it’s a perfect fit for the Tom Bihn Snake Charmer, which is an excellent pouch for organizing and carrying charge cables and other electronic bits.

Tom Bihn Snake Charmer in the bottom pocket of the Synapse 25

Tom Bihn Snake Charmer in the bottom pocket of the Synapse 25

There are two side pockets.  The right one has an Ultrasuede-lined inner pocket that can fit today’s larger smartphones (my Motorola RAZR Maxx is shown in the pic below) and an O-Ring to which I’ve clipped my sunglasses case.

The left pocket has a small admin area with two slots for knives/multitools and another for a pen. It’s a shame that the design team at Tom Bihn couldn’t figure out a way to include a larger admin area with more slots.  The pocket does have yet another O-Ring and I’ve used that to attach a small light via an utility strap.


The lower top front slip pocket is a great place for stay items like keys, backup cards/money or a camera.  This time I’m carrying my pocket pouch attached to an O-Ring and an Ultrasuede cleaning cloth for my electronics there but it varies depending on the day.


The upper front zipper houses the bottle pocket.  Other than the dual insulated pockets on the Camelbak Urban Assault, I’ve not found a better setup on a bag to carry a Nalgene bottle.  With the filled bottle, the weight actually stabilizes the pack since the pocket runs down the center of the bag.

Synapse 25 with a 32 ounce Nalgene bottle

Synapse 25 with a 32 ounce Nalgene bottle

For those who might want to use insulated bottles, a 24 ounce Polar Bottle fits quite nicely also.  In fact, even with the reduced size I prefer the Polar in the Synapse 25.  With it’s taller profile, it just seems to carry better.  The pocket will also fit a 1.0 -1.5 liter hydration reservoir although to me the hose routing isn’t that optimal given the location of the pocket in relation to the straps (your mileage may vary).

Synapse 25 with a 24 ounce Polar Bottle

Synapse 25 with a 24 ounce Polar Bottle

One more point on the subject of hydration.  I’ve not been able to find a comfortable way to carry a full sized bladder in the main compartment.  There is no centered O-Ring to hang one and using the internal pocket (on the side opposite from the back panel) pulled the pack down placing more weight on my shoulders making the entire rig uncomfortable.  Just an fyi for anyone thinking of that type of setup.

As for the main compartment, one of the improved features of the Synapse 25 is the Cache with Rails system.  We did a short video to highlight it’s benefits.  If you travel, this enhancement alone might be worth the upgrade.  There are also a couple of O-Rings but I would have rather had them on the opposite side.  In practice, they tended to interfere with the Cache depending on what I had clipped to them.  But, if you’re not carrying a laptop, it doesn’t hurt to have them there.

I also had room to store more items in the main are including a composition book with cover and a Tom Bihn Stuff Sack with a hat and gloves in case the weather turns nasty.


On the opposite panel is an elastic pocket where I’ve stored a light jacket and my tablet.  There are two additional webbing loops where you could attach another cache to better protect a tablet or  even a second laptop.  I’ve done a mod here and attached two ITW Web Dominator clips.

Synapse 25 with ITW Web Dominators

Synapse 25 with ITW Web Dominators

Using those clips, I’ve attached my Maxpedition Janus pouch, which contains my first aid kit and miscellaneous EDC items.


The Janus features a somewhat unique horizontal PALS webbing setup but other pouches with horizontal webbing if the spacing is right would work here.  And hopefully Tom Bihn will release additional accessories for the Synapse 25 that will clip in via Gatekeepers – like the Cache with Rails.

The other benefit to the Web Dominators is that Key Straps can be clipped to the paracord, which provides another set of attachment points if needed.

Overall, the Tom Bihn Synapse 25 meets the majority of the criteria we look for in an EDC pack.  It’s large enough for a tall person to wear without looking like you’re carrying something that should have Dora the Explorer printed on it.  It’s office friendly, low profile, has good organization and it’s light weight  (weighing an amazing 1.79 lbs empty).  It’s TSA checkpoint friendly with the addition of the Cache with Rails and small enough to carry onto an airplane if needed.  Given all this, the Synapse 25 is now our reference mid-sized EDC pack here at Loadedpocketz and we don’t see it being dethroned anytime soon.

The Synapse 25 comes in a variety of color combinations and retails for $170.  It’s available exclusively for sale here on Tom Bihn’s website.

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19 Responses so far.

  1. […] Loaded Pocketz has posted their review of the Synapse 25 (lots of photos). […]

  2. […] Read the full review at Loaded Pocketz. See also: the Synapse 25. […]

  3. John says:

    Thanks for the great review! Do you prefer the GR1 or the Synapse for EDC? Both packs appear to be exceptional.

    • Blaine B. says:

      John, both packs are exceptional in different ways. I haven’t carried the GR1 enough to fully form an opinion on it. But, I think it really depends on how you intend the use the pack. If you plan to travel then I’d say the Synapse is the better choice since it’s checkpoint/TSA friendly and provides better organization for travel documents, electronics, personal items, etc. I think it would also be excellent in a commuter/office EDC role or for weekend around town excursions.

      If you plan on using the pack for outdoor activities (hiking or even a GRC) in addition to the things I’ve mentioned then the GR1 would be a better all around choice. I really don’t intend to use the Synapse in situations where I’d normally carry a 3L Hydration system. It’s really not designed for that. And the GR1 is probably the better loading bearing pack (although I need to carry it more to validate that).

      Hope that helps.

  4. John says:

    Hi Blaine,

    Your thoughtful comparison of the GR1 and the Synapse 25 is greatly appreciated! I have a Goruck Radio Ruck, so the Synapse will soon be added to my backpack collection. Thanks again, John

  5. Henry says:

    Hi Blaine! Are you thinking about doing a comparison of the Synapse 25 and the Smart Alec? My Synapse 25 is on the way, so you know which decision I made, but I am still somewhat unsure. It basically seemed to me like the Smart Alec was more versatile, but the additional cost of pouches/other organizers needed to get the same kind of organization that you get by default with the Synapse put it in a higher price tier.

    In any case, I would be interested in hearing your thoughts!

    • Blaine B. says:

      Henry – your line of thinking is valid. Also, the Smart Alec is better if you need to haul bulky items (like a change of clothes) since the main compartment is larger. But, my next Tom Bihn article will be a comparison of the two packs. So stay tuned.

  6. Henry says:

    Ah, thanks for the reply! I just got my Synapse 25, and it’s pretty nice, but I’m not quite ready to commit…although I love the construction and materials, the small main compartment seems like it would be difficult to one bag with. Still thinking…

    On another note, have you seen the Arc’teryx Sebring 25? It seems to combine the top-loading/side pockets organization of the Smart Alec with the ability to open the entire front panel like the GoRuck GR1. I’m sure that the general construction is not as high quality, but the design is interesting.

  7. Henry says:

    Oh, and another thing – I managed to fit my 3L CamelBak Unbottle in the main compartment by adding a pair of single gatekeepers to the webbing loops on the inside and threading the nylon strap at the top of the Unbottle through them. The main zipper has to stay open to let the hose through, but at least there’s an option for relatively comfortable carry.

  8. Liam Byrnes says:

    I’d love to see the synapse/smart alec compare post..

  9. Ryan says:

    Would love to see the comparison between Synapse and Smart Alec as well. Currently own a 19L Synapse and am considering the upgrade as I’m a 6’2″ 190lbs guy.

    Love the website Blaine!

    • Blaine B. says:

      Thanks Ryan! The Synapse/Smart Alec comparison is coming. There are a few other reviews I have to knock out first. Stay tuned. In the meantime, I took a couple of pictures and shared them in a thread on EDC Forums here. I also shared a couple of quick thoughts on the differences here.

  10. Chris says:

    Great review! I’ve been debating on the Smart Alec or the Brain bag for a week or so but now I am debating on the Smart Alec or the Synapse 25. Is the comparison review for these two bags still in the works? Also by any chance the side pocket that has the three smaller pockets for pens and multitools, will it fit one of the Maxpedition pocket organizers? If so which would be the biggest do you think would fit? Thanks, keep up the great work.

  11. […] Per this Tom Bihn video, I'd guess Snake Charmer. It's also noted on the Loaded Pocketz review how well the Snake Charmer fits in that pocket. Tom Bihn Synapse 25 Backpack ReviewLoaded Pocketz […]

  12. […] everyone. I decided to go with what loadedpocketz.com did by utilizing ITW web dominator clips on a maxpedition janus pocket that I was considering […]

  13. Hi – awesome review. I’m curious – what pouch is that shown in your last picture?

  14. Anonymous says:

    […] is where things start to take an interesting turn. Several weeks ago I found a very interesting post, whereby the author hacked his Maxpedition JANUS bag into the main compartment of this Synapse 25 […]

Comments and Questions are Welcome!

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