The Seek Outside Peregrine 3500 (57 L) is an external frame backpack with a breakaway load carrying system that is capable of hauling up to 100 pounds. Designed to meet the needs of backcountry explorers who want an off-trail backpack for day hikes or multi-day trips, the Peregrine 3500 is loaded with features that make it a compelling choice where heavier and more awkward loads may be necessary. Whether your thing is stalking big game in Colorado or Wyoming or just volunteering for a weekend of backcountry trail maintenance, this pack is supremely comfortable, easy to use, and expands to carry meat, antlers, hand tools or expedition supplies.
Seek Outside Peregrine 3500 Backpack
Versatile Breakaway Pack
Specs at a Glance
- Best Use: Expedition backpacking, backpack hunting, guiding, trail maintenance
- Weight: 4 lbs 2 oz
- Capacity: 3500 cubic inches (57 liters)
- Frame: external, field adjustable 24”-28”
- Hip Belt Size: five sizes for 29” to 48” waists
- Shoulder Harness Adjustment: 15” – 22” torsos
- Roll Down Volume Range – 3500 ci (57 liters) to 2500 ci (40.9 liters – at frame height)
- Main Pack Bag – X-Pac waterproof material with roll-top closure
- Side Pockets – 500D Cordura
- Suspension – 500D Cordura and 3D Mesh
For complete specs, visit the Seek Outside Peregrine Product Page
Backpack Organization and Storage
The Peregrine 3500’s main pack bag is similar to many ultralight backpacks on the market today. The main pack bag is a large round stuff sack with a roll-top closure and several large external pockets, but this is where the similarities end and the Peregrine’s unique feature set begins.
Main Pack Bag
The main pack bag, made from a waterproof fabric called X-Pac, is extremely robust and covered with a crosshatch ripstop weave for heavy-duty off-trail use. This part of the pack is virtually waterproof except along the zipper, which runs from the top of the pack bag down the side to the bottom. A flap covers the zipper, but this seam is the only area on the main pack bag that is likely to allow moisture to penetrate. Seek Outside recommends seam sealing along the zipper seams in extremely wet conditions (such as canyoneering, where floating a pack in water may be necessary), but for regular rain, the pack does a fine job keeping the contents dry without the need for waterproof stuff sacks or an external rain cover.
The Peregrine 3500 has five external pockets. The two side pockets run nearly 2/3 the length of the main pack bag and are designed long ungainly gear ranging from axes and packraft paddles to spotting scopes, tripod, and rifles. These pockets are large and are cinched down with a drawcord at the top (to keep contents from spilling out). They also have two compression straps on the sides.
The hybrid mesh/Cordura pocket on the front face of the pack is designed to stretch and expand away from the main pack body to hold gear and clothing that you may need to access quickly throughout the day. Two zipper pockets parallel each other and run from the top to the bottom of the expandable rear pocket. These two security pockets are perfect for storing things that you can’t afford to lose and work well for a map, compass, knife, and other low profile items you want to keep close at hand.
All of the external pockets are made from 500D Cordura fabric with the exception of the heavy-duty mesh stretch panels on each side of the rear pocket. Combined with the X-Pac main bag, this pack is heavy duty and will stand up to abuse when bushwhacking or backcountry hunting.
External Attachment and Compression System
The Peregrine 3500 has six side compression straps, three on each side, and a “V” shaped strap runs over the roll top. One of the key features of this pack is the connection of the compression straps to the external frame.
The compression straps are quite long and made from nylon webbing that is attached to the pack with plastic gatekeeper clips. These clips have wire gates that prevent the webbing from slipping when the strap is tensioned while locking the straps and securing the load to the pack bag. Gatekeepers open easily with bare hands or while wearing gloves by simply letting off a little tension on the strap and then squeezing the buckle until the gate releases.
One thing that makes this pack unique is the expandability of its compression system to accommodate a load behind the main pack body. By loosening the side and top compression straps, the main pack body pulls away from the frame so that additional gear, tools or meat, can be loaded next to the frame and then the main pack bag compressed back against the additional load. This style of external frame backpack is called a breakaway pack.
A removable load shelf on the bottom of the pack attaches the frame to the main pack body and spans the void created by pulling the main pack bag away from the frame. The load shelf uses the same webbing and gatekeeper clip system to keep the additional load from slipping through the bottom of the pack. In the past, hunting packs accomplished this by having a fixed 90-degree frame and webbing “meat shelf” at the bottom of the pack, but the Peregrine’s load shelf meets that purpose by keeping it simple, light, adjustable, and removable.
Backpack Frame and Suspension
The Peregrine 3500 is built on an adjustable length external aluminum frame that is common to all Seek Outside packs. This frame system is the hinge upon which all of Peregrine’s varying configurations and size adjustments pivot, and coupled with the simple webbing and gatekeeper clip lashing system, the pack is easily adjusted to fit different torso lengths and to accommodate numerous load types. The load lifter angle is adjustable to accommodate larger loads, and the pack frame is rigid and stable as the carrying weight is driven onto the hips, and not spread between the shoulder and the hips as is common in lightweight backpacks.
The Hip Belt
The Peregrine’s hip belt is a thing of beauty, especially when carrying loads that are north of 45 pounds. The belt is 5” wide, and thick with a double buckle system that keeps it secure and comfortable around your hips. Once tightened up, the belt holds tight and the padding makes the extra weight easier to carry. I have never used a hip belt as comfortable on the one on this pack, and an effective and robust hip belt is mission-critical when carrying heavy loads.
The belt is attached to the bottom of the frame and not to the main pack body. The padded hip belt keeps the load at your core and away from your shoulders. It also has webbing loops to attach hip belt pockets, water bottle holders or even a pistol holster, but these are sold separately.
The Peregrine 3500 is a pack that was designed for hunting, specifically big game hunting for Elk, Caribou, Deer, and the like. The idea for a pack like this one is that a hunter, in a state like Colorado, Wyoming, or Alaska would head out into the wilderness on a 1-3 day hunt to stalk game from a distance. When and if the hunter makes a kill, there are no trucks or 4-wheelers to haul that kill out; the animal is butchered in the field, quartered, and then lashed to a pack and hauled out on foot. That the type of load that the Peregrine is built to haul.
While hunting, the Peregrine 3500 allows the hunter to bring all of the essentials for warmth, for cooking, sleeping, and keeping dry as well as the tools of the trade, such as a rifle, ammunition, a spotting scope, ground blind, and a tripod. With the breakaway frame system, the hunter can field dress a large animal and place the quartered sections into a leakproof game bag, attach that bag to the frame and compress the main pack bag against the game bag. This will produce a heavy, but manageable load to carry out of the backcountry.
Because the Peregrine 3500 is so configurable, there are also options for how the game bag can be lashed to the frame. For instance, if the hunter was only going out for the day and had less gear, the main pack bag could be rolled down to half the height of the frame, and then the game bag could rest on top of the main pack bag and tight against the frame. This would distribute the weight of the load differently by using the main pack bag as the meat shelf, and can be less awkward should there be a smaller amount of meat to carry.
When you look at this pack for the first time, the webbing straps, attachment points, and various configuration options can feel a bit complicated. But once you start packing it, the pack becomes much easier to understand and utilize. Everything on this pack works off of the external frame, and once you understand that about the Peregrine 3500, it becomes easy to see how this can be much more than just a hunting pack.
Those of us that use trails know that trails need maintenance and that volunteers do most of that work. When going out for a weekend-long trail maintenance trip, there is a need to carry more than just your backpacking gear.
The Peregrine 3500 is great option for trips that require carrying tools ranging from pulaskis and axes to chain saws. Tools don’t fit well in conventional backpacks. They can add considerable weight and be quite awkward to carry. This pack solves that problem by being expandable enough to carry an awkward load while having the suspension necessary to make it relatively comfortable.
Multi-day Backpacking and Base Camping Trips
Longer and more elaborate trips into the backcountry require carrying more food and gear. Whether you are carrying extra supplies for a large group, taking a heavier load when trekking with smaller or less experienced hikers, or hauling gear for a large base camp; the Peregrine 3500 is a good option for shouldering these cumbersome loads, while being flexible and light enough to use for side trips from a base camp. If you’ve ever tried to haul a case of beer or two in an internal frame backpack, you’ll immediately understand the benefit of owning of breakaway backpack with an external frame.
Comparable External Frame Breakaway Backpacks
|Exo Mtn Gear K3 3200 (52L)||5 lbs 1 oz||$619|
|Mystery Ranch Terraframe 50L||5 lbs||$400|
|Mystery Ranch Selway 60||5 lbs||$500|
|Seek Outside Peregrine 3500 (57L)||4 lbs 2 oz||$489|
The Seek Outside Peregrine 3500 is an external frame breakaway style backpack that designed for backcountry hunting, but adaptable for many other uses. Whether hunting, pack rafting, hauling large loads on longer backpacking trips, or just volunteering for a weekend of trail maintenance, this pack can comfortably adjust to carry the heavy, awkward loads that a conventional backpack just can’t handle. With a wide, cushioned hip belt, a weatherproof pack bag, and a versatile compression system, the Peregrine 3500 is a robust backpack that can adapt to help you meet new challenges in the wilderness. I’m glad I have one in my gear closet and look forward to using it off the beaten track.
Disclosure: Seek Outside donated a backpack for this review.SectionHiker is reader-supported. We only make money if you purchase a product through our affiliate links. Help us continue to test and write unsponsored and independent gear reviews, beginner FAQs, and free hiking guides.
Great review and nice to add some variety to the topics usually covered.
Not many places will give you a use-case “if you have ever carried a case of beer” ?
Minor typo under the photo in frame and suspension section “Numerous steps” should be “ numerous straps”
Love my SO Divide as my everyday- driver pack. I keep my more fragile ultralight pack for longer trips to extend its lifespan
The SO packs really do define toughness and raise the bar for off-trail prowess (and beer hauling).