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Seek Outside Gila 3500 Backpack Review

Seek Outside Gila 3500 Backpack Review

The Seek Outside Gila 3500 (57L) is an 2 pound 15 ounce external frame backpack capable of carrying heavy loads, up to 100 pounds. It’s made with a waterproof laminate fabric called XPac which is more durable than Dyneema Composite Fabric (formerly called cuben fiber) and less expensive. While the weight carrying capacity of the Gila is overkill for ultralight thru-hiking, the comfort provided by the pack for heavier 25-45 pound loads is quite impressive. External frames are well ventilated, so sweating isn’t an issue. The wide hip belt provides an excellent wrap around your hip bones and doesn’t slip, while the stiff frame keeps the pack weight off your shoulders. Let’s take a closer look at what makes this pack tick.

Seek Outside Gila 3500 Backpack



The Seek Outside Gila 3500 (57L) is an adjustable-length, external frame backpack that's ideally sized for lightweight backpackers who want a ultralight-style pack that weighs less than 3 pounds to carry loads in the 30-50 pound range. This is a weight range that's beyond what many other ultralight-style and cottage lightweight backpacks can carry today, but well within the Gila's wheelhouse.

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Specs at a glance:

  • 42-47 ounces
  • Frame: external, adjustable torso length
  • Fabric: X21 XPac; other grades of XPac are also available
  • Suspension is 500D Cordura and 3D spacer mesh. Hypalon and 500D Cordura reinforcements
  • Sizing:
    • 14″ – 20″ torsos without extensions , 18″ – 21″ with 2 inch extensions.
    • One size harness micro adjustable to any torso length within fit range
    • Interchangeable hipbelts in three sizes, to fit waists from 29″ to 42″
  • Max weight limit: 100 pounds
  • MSRP $339

Internal Organization and Storage

The Gila 3500 is laid out like an ultralight style backpack with a roll top closure, a long rear mesh pocket, and side water bottle pockets. The rear pocket is made with heavy duty mesh to prevent ripping while the side packets are hard faced with 500d Cordura for extra durability. There are two webbing loops inside the pack bag to hang a reservoir with a single hydration port behind the shoulder harness.

The Gila 3500 has a long mesh back pocket that can store a ton of gear
The Gila 3500 has a long mesh back pocket that can store a ton of gear

The side water bottle pockets can hold two 1 liter water bottles, which are reachable while you’re wearing the backpack. The pockets have a fabric slit in the bottom to drain water, but you need to be careful not to put small items there, lest they slip out. There’s also an elastic cord with a cord lock that runs through the top of each side pocket, so you can cinch it tight and keep taller items like tent poles, a paddle, or fishing rod secure. The lower side compression strap runs above the side pocket so there’s no need to ever routed it through or over the pockets like other backpacks.

The Gila doesn’t have hip belts pockets, although they are available as an optional add-on. The outside of the hip belt has a pair of webbing straps to attach them to. Both of the shoulder straps have external daisy chains which are convenient for hanging a GPS or camera pocket.

Gatekeeper compression strap buckles
Gatekeeper compression strap buckles

External Attachment and Compression System

The Gila has three tiers of side compression straps that give you a lot of flexibility to lash gear to the side of the pack or compress your load. The webbing straps are not long enough to loop behind the backpack, although the hardware doesn’t prevent you from running you own webbing straps there (for example, to attach snowshoes to the back of the pack). The side webbing straps are attached using plastic gatekeeper clips, which are like bachelor buckles but with wire gates to prevent the webbing from slipping when the strap is not tensioned. You can open the gates while wearing gloves by simply squeezing the buckle, which will pop the gate open.

The roll top closure buckles closed on top of the packbag and is held in place by a Y strap.
The roll top closure buckles closed on top of the packbag and is held in place by a Y strap.

The Gila also has a pair of sleeping bag straps at the base of the packpack that can be used to attach gear, like a tent or sleeping bag, to the bottom of the pack. You can use these to hold a bear canister or strap it under the Y strap on top of the pack.

Backpack Frame and Suspension

The Gila 3500 uses the same adjustable length, external frame suspension system as all of Seek Outsides other backpacks. The frame and suspension system is nothing short of ingenious, providing a level of modularity and many types of adjustments that are not available on conventional internal frame backpacks.

Adjustable torso length

First off, the torso length of the Gila 3500 is adjustable by raising and lowering the height of the shoulder harness. If you have a very long torso, you can add vertical extensions to the external frame to make the torso length longer.

The shoulder pads can be moved up or down to adjust the pack's torso length
The shoulder pads can be moved up or down to adjust the pack’s torso length

Adjustable load lifter angles

The angle of the load lifter straps is also adjustable so you can maintain them at a 45 degree angle. To change the angle, you raise or lower a buckle the runs along the front of the shoulder strap. Many high-volume expedition packs have this feature and it’s quite useful to counter loads that pull you backwards and off balance.

External frame

The external frame is made using aluminum tubing and slightly curved to conform to the curvature of your back. Being an external frame, back ventilation is good because there’s an air gap between your shirt and the pack bag.

The frame is extremely rigid and there is no sag of the pack bag against your back. If you want, you can lengthen the torso so that the entire load rests on your hips, very unlike an internal frame pack where the weight is always split between your hips and shoulders by design.

The pack bag is secured to the frame with webbing loops, locking nuts, and pole sleeves that keep it properly positioned. If you want, you can replace the pack bag provided with the Gila with a higher volume version sold by Seek Outside or attach additional accessories. Yes, this one frame works with many packs.

The frame has a noticeable curve which helps direct the load into the hip belt and keep it off your back for better ventilation.
The frame has a noticeable curve which helps direct the load onto the hip belt and keep it off your back for better ventilation.

Horizontal stay

There is a horizontal stay positioned behind you back that keeps the pack bag from barreling or bulging into you back if you overstuff the pack bag. It’s quite effective. This can be an issue on any roll-top backpack if you try to over stuff or over compress it.

Comparable External Frame Backpacking Packs

Make / ModelVolume (L)WeightPrice
Kelty Trekker65L5 lbs 2 oz$180
Kelty Yukon48L5 lbs 1 oz$170
Kelty Tigoa90L5 lbs 9 oz$200
ALPS Mountaineering Bryce59L4 lbs 13 oz$140
ALPS Mountaineering Zion64L4 lbs 15 oz$170
Mystery Ranch Terraframe50L, 80L5 lbs$400
Seek Outside Gila57L2 lbs 10 oz$339
Seek Outside Divide74L2 lbs 12 oz$349
Seek Outside
Unaweep 4800
79L2 lbs 11 oz$399
Vargo ExoTi AR246L2 lbs 12 oz$300
Vargo ExoTi 50L2 lbs 11 oz$300
ZPacks Arc Blast55L1 lb 5 oz$325
ZPacks Haul62L1 lb 8 oz$299

Hip Belt

The padded hip belt is quite wide (5″) and provides an outstanding fit that won’t slide down your hips even if you wear it fairly loosely. It’s attached to the bottom of the frame and floats freely, conforming to your anatomy, rather than making you conform to its shape like many internal frame backpacks.

Seek outside changed their hip belt about six months ago (on all of their packs), shifting from a single strap and single buckle to two buckles, attached to two straps running along the hip belt. This was to remove a single point of failure, while improving the wearer’s ability to tighten or loosen the top and bottom edges independently. While the new hip belt does improve the fit, it adds two long straps to the hip belt which can get in the way of each other when you attach and adjust the hip belt. Seek Outside has a good video on their which shows how to manage these straps with tri-glides, which helps reduce their nuisance factor.

Closeup of the improved Seek Outside hip belt
Closeup of the improved Seek Outside hip belt


The Seek Outside Gila 3500 (57L) is an adjustable-length, external frame backpack that’s ideally sized for lightweight backpackers who want a ultralight-style pack that weighs less than 3 pounds to carry loads in the 30-50 pound range. This is a weight range that’s beyond what many other ultralight-style and cottage lightweight backpacks can carry today, but well within the Gila’s wheelhouse.

There are lots of good reason why people have to carry this much weight on a backpacking trip.

  • Wilderness backpackers that don’t have easy access to towns for resupply have to carry more gear, food, and fuel
  • Winter backpackers have to carry more sleep insulation, food, fuel and technical gear
  • Guides, trail maintainers and other wilderness professionals have to carry extra communication, medical, and search and rescue gear
  • Dads get stuck carrying their own gear plus their kid’s gear and food on backpacking and camping trips.

If this describes you, I’d recommend checking out the Gila 3500  and its adjustable length external frame suspension system. Carrying one of Seek Outside’s external frame backpacks is nothing like that old Kelty or Wenzel pack you carried as a kid. Based on the Seek Outside external frame, the Gila 3500 is well sized and appointed for lightweight backpackers who have to carry more weight than they might like, but appreciate the layout of an ultralight-style, roll top backpack pack.

Disclosure: Seek Outside loaned the author a backpack for this review.

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  1. I just love the way my Unaweep 4800 fits. I like the old single-buckle pull forward design of the hipbelt better, but not for the single buckle, but for the pull forward. I have one pack where the hip belt pulls back. I’ll never buy another. If Seek Outside wanted dual buckles, why not copy SMD’s design on the Fusion 50 and 65? Dual buckles, pulls forward. Simple.

    Other than the hipbelt, I’m a big fan of their other design changes since I bought my pack in 2014. I keep being responsible and so far have managed to avoid the temptation to purchase a new packbag, although my current CF hybrid Unaweep packbag is starting to show some wear.

    • SMD or ULA. I think they wanted a hip belt with Molle attachment points for their hunting customers. The new pack changes are a good thing but I still like the old design enough (I have custom 4800) that I’m going to keep and not replace.

    • I definitely agree on the hipbelt. I hate hate hate the pull back, I can’t get the hip belt as tight as I want. I’ve taken to capturing the buckles on one side so the straps have to come all the way across, giving me a pull forward on that side, but also creating a bunch of loose webbing to manage.

    • I for one find the new hipbelt much better than the old one. I upgraded because I was curious It is a little thinner, and the dual buckles really allow fine adjustment so you can get the hip tension you want. Overall I find it molds to your hips better than the old belt because of this. For me it is a noticeable difference. Just keep one side of the buckles all the way pulled to the side, then when you click it in it is like a pull forward belt but I really don’t know you say that the you can’t get the hip belt as tight as you want. I feel like I can get the new belt just as tight.

  2. There’s a few bits and pieces that you can take off to get the weight down towards the 2lb and change that a lot of the UL packs come in at.

  3. When I bought the Divide earlier this fall they also provided a large single buckle for the hipbelt, so the option for 1 buckle is still there. The two buckle system is more comfortable.

  4. How about the burning question on my mind and one of the major differences between classic external frames and internal: How well does it move with you (or conversely, throw you off balance)? Especially off when off trail or scrambling?

    The old school external would drop the weight squarely on your hips but it felt like with one slip you’d topple over and careen down the mountain as the weight was further away from your center of gravity.

    Internals solved this problem at the expense of ventilation and more weight on your torso.

    How does this pack deal with such conundrums?

    • Depends to a large extent on how you pack it (heavy on bottom or top) and how tight you pull on the shoulder straps. It carries a lot like an internal frame pack if you put more of the load on your shoulders. But you can loosen them up completely and carry the entire load on your hips if you want.

  5. Maybe an idea for an article unless for us newbies you’ve already done this. What exactly is “cottage”? I think I understand it to be some sort of very small equipment manufacturer. Would like to know more overview about them including who the players are (or how to shop for), what their positioning is in a world of large companies, and their business cases as wells turnover/lifespan in the market. Seems like a lot of them have very specialized products that for some reason the big guys don’t address. My 2 cents on an article suggestion, and thanks.

  6. Cottage mfg is usually started by someone who noticed a need and started producing the product in a small scale, in a cottage. Seek Outside is one example, Lightheart Gear, Hyperlight Mountain Gear, Six Moon Designs, Mountain Laurel Designs, Ragged Mountain Equipment, Z-Packs, Enlightened Equipment, Black Rock Gear all started in someone’s garage or basement and have since expanded. Usually very responsive to custom modifications and inquiries, American Made products, etc. I usually look at the smaller, niche companies before I look elsewhere.

  7. Phil,

    Can you tell me what a pull back belt strap is? Is it like the osprey belts?

    Very interested in these packs. Is the divide still available?

    • It’s the direction you pull on the straps. Some belts pull forward and some pull back. It’s hard to say which is better because it depends on many factors. If you need a very tight fitting hip belt, the pull forward straps are easier to tighten. The pull forward mechanism is called the scherer cinch after the kelty product designer who invented it. He’s the same guy who makes the deuce of spades trowel. Check the mfg website for product availability.

  8. Given infinite money I’d most likely love the gila. But given the frame capability, volume, weight, and price points I think the Divide is a much better pack.

    • I agree. I like the pocket layout on the Gila, but if you’re going to have an external frame pack, you might as well use it for carrying bigger loads. Honestly, offering external frame packs in lower volumes diminishes the unique benefits of having an external frame. The 60 liter Gila is about as small a pack that can really benefit from one.

  9. I’ve been casting about for a winter-specific pack suitable for day and overnight outings—large volume, accommodating of external lashing, etc. Of the Seek Outside offerings, the Exposure 5000 is most appealing to me, as i’m fond of organizing options (external pockets, divided main compartment, etc.). The Exposure lacks a divided, bottom ‘sleeping bag” pocket, but has the large, outer center pocket above the mesh pocket that the other SO packs lack. Plus, it has the perimeter zipper for “panel” access, so stuff in the middle or bottom of the pack can be accessed without rifling down from the top opening. A big plus for me.

    There aren’t many options for updated external-frame designs these days. Vargo has a couple of lighter versions that are appealing. Alps (old-style, heavy). Same with Kelty. Osprey has the Xenith, with a kind of perimeter, external-but-covered-in-fabric frame.

    Having looked at all the options i can find, i think i’m coming down to either the Xenith (top lid with multiple compartments, lower main-bag compartment, but heavier at 5+ pounds) and the Exposure (lighter, truly external frame more accessible for lashing, but fewer pockets).

    Anyone have any experience with or feedback on the Exposure? There aren’t a lot of reviews out there.

    (And i’m not sure why Kelty is getting dissed. I’ve been using the Tioga 5500, which carries moderately heavy weight with aplomb for me. Never any shoulder pinching or pain, chafing from waist belts, etc. Organizational options up the wazoo. Bombproof. The only real problem for me is the weight—5+ pounds—but even then, it has a better volume-to-weight ratio than some similar-sized internal-frame packs.)

  10. When carrying 30 lbs or more, which pack do you find more comfortable, the Gila or the Mariposa?

    • Really different packs. It’s hard to compare them.

      • I realize they are quite different. Still, I would love to hear which one feels more comfortable to you when carrying around 30 lbs if you can still remember it. This is near the the upper recommended weight for the Mariposa and I wonder if it is still comfortable at that weight when compared to the Gila. I hate heavy carries with an uncomfortable pack and I would gladly take a weight penalty of a pound if the pack feels much more comfortable on my back after a resupply or when having to carry lots of water. Also, being able to use a pack for more than one thru-hike without trashing it would be really nice.

  11. ok. When you get up to 30-35 pounds, the Mariposa starts to max out. I ounce tried to carry 40-45 pounds with it and it almost killed me (figuratively speaking). The Gila handles that with ease, in part because it has such a wide hip belt and the frame won’t collapse because it’s metal. The Xpac will also be much more durable than the robic nylon on the Mariposa. You’d have to try really really hard to trash the Gila on a thru-hike. No so much with a Mariposa. I’ve shredded one of them in a day.

  12. Is the Divide just a larger version of the Gila? If so, it seems like the better way to go given it is larger and only 2 oz heavier but I may be missing something. Thoughts?

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