ULA Circuit Backpack Review

When I launched my thru-hiking career on the Colorado Trail in 2015, I did a lot of research online to find gear I thought would work for me. I’m pleased to say that with just a couple of exceptions — I’m not an inflatable pad guy, it turns out, and my hiking kilt gave me monster chafe — I’m pleased to say I still have and can use most of that gear.

Among the most consequential choices I made — any long-distance hiker makes, for that matter — was my backpack. I went with ULA’s Catalyst, at 75 liters, the company’s roomiest beast. I loved that pack, which I used on both the CT and for the entire Appalachian Trail a year later. I still love my Catalyst, though I have moved on to a less-roomy, lighter-weight pack.

But this summer, I got the chance to test drive the Circuit, ULA’s self-proclaimed “favorite child,” and the most-used pack on the Pacific Crest Trail for three years running according to Halfway Anywhere’s annual trail survey. The Circuit is 9.3% less roomy and almost 16% lighter than the Catalyst but is otherwise much the same pack.

ula circuit backpack

The ULA Circuit comes in five colors: purple, teal, royal blue, green, and black. Clay Bonnyman Evans photo.

ULA Circuit Specs

MSRP: $279.99+ (depending on customizations)
 68L/4200 cubic inches
Weight: 37.3 ounces
Max Load: 35 pounds (15 pounds recommended base-weight max)
Materials: ULA 400 Robic or X-Pac

Circumstances of Review

While I pondered taking the Circuit on my recent quick traverse of New Mexico on the Continental Divide Trail, in the end, I went with my tried-and-true favorite, not wanting to take chances. But I’ve now used the Circuit extensively during non-strenuous day hikes. While the Circuit comes standard with durable 400 Robic fabric, I tested a custom Circuit made with cutting-edge X-Pac fabric.


You can choose from four torso sizes and six hipbelt sizes and two types of shoulder straps (“J” and “S”). I’ve always been tickled at ULA’s choice of gorgeous colors—green, teal, royal blue, purple and black. You can also build a custom Circuit, specifying the material and color of virtually every part of the pack as well as tweaking the top and bottom straps.


My trusty ULA Catalyst was plenty comfortable, but I did experience some brutal chafing on my shoulders, hips, and the small of my back.

I’m pleased to say that the ULA Circuit gave me no such problems (though again, I did not use it for a long series of 25- or 30-mile days). After trying on my old Catalyst, it’s clear that the company has either tweaked its design in general or the Circuit is built better for my body.


When I was a newb, I didn’t know how much space I’d need, and in the 6,600 miles of long-distance hiking since, I’ve significantly reduced my kit. So, at 68 liters/4200 cubic inches, the Circuit has plenty of room. It breaks out as follows:

  • Main body: 2,400 cubic inches
  • Front (I think of it as the back…?) mesh pocket: 400
  • Side pockets: 800 (400 each)
  • Extension collar: 500
  • Hipbelt pockets: 200 (100 each)

ULA Circuit Features

  • Internal suspension hoop
  • Single aluminum stay — bendable, to adjust for airflow between pack and your back
  • Padded back panel
  • Contoured shoulder straps — I’m a “J” strap guy, but as mentioned, you can order “S” straps
  • “Front” mesh pocket and shock cord
  • Dual hipbelt pockets
  • Adjustable side pockets
  • Rolltop closure
  • Side/top compression straps
  • Ice axe/pole retention loops
  • Sternum strap
  • ULA 400 Robic bottom panel
ula circuit mesh pocket

The ULA Circuit has a 400-cubic-inch exterior mesh pocket with a shock cord, plus two generous side pockets and hip pockets, adding up to 1,900 cubic inches of exterior storage. Clay Bonnyman Evans photo.

Suspension Hoop

The Circuit uses a 1.2 oz carbon-fiber and Delrin hoop in conjunction with a dense internal foam pad and the adjustable aluminum stay to provide solid support and stability without limiting range of movement or feeling bulky or stiff.

Padded, Contoured Hipbelt

I love the Circuit’s hipbelt, which feels comparably comfy to my old favorite. It’s great that ULA’s hipbelts are easily switched out (but tightly Velcroed in place), in case the hiker gets too skinny (or, I suppose, fat) for the belt originally ordered.

Exterior Mesh Pocket and Shock Cord

The Circuit offers tons of room and two ways to carry a sleeping pad, water bottles, peeled-off layers, and the like on the exterior of the pack. The pocket is stretchy and roomy—plenty of room for stuffing!

Uber-Tough Material

ULA’s Robic 400 nylon (the material that comes standard with the pack) is some tough stuff, indeed, feeling considerably sturdier than the material on my old Catalyst (which is incredibly tough and still going strong, seven years on).

The ripstop-reinforced material is incredibly tear- and abrasion-resistant, reinforced. It has three-pass Teflon DWR and a three-pass PU Coating for water resistance, and I can attest after walking through an Atlantic downpour that it fends off the wet stuff.

I tested the Circuit with X-Pac fabric instead of Robic (you have to order a custom Circuit to get this special material). ULA describes X-Pac as “ultralight, ultrastrong, abrasion and tear resistant, and highly waterproof. In short, it’s perfect for making outdoor gear, and we think you’ll like it!”

READ NEXT – The Best Backpacks for Thru-Hiking

ula circuit robic 400

ULA’s Robic 400 nylon material is incredibly tough. The Circuit has a collar extension that provides 500 cubic inches of additional space. Clay Bonnyman Evans photo.

ULA Circuit Pros

Carrying Capacity

The main compartment is plenty big enough for all my basics, tent, sleeping bag, clothing, food bag, stove, personal items kit, etc. The extension collar will come in handy when on a particularly long food carry or when packing winter gear. I love big hip pockets, and you can really stuff a lot in the Circuit’s 1,900 cubic inches of exterior storage capacity.


All that, for a pack that’s under 2 and a half pounds.


I truly love that ULA offers a variety of great colors (though I do miss those crazy red and orange ULA packs of yore!).


In this area, the Circuit beats my current fave hands-down. You will have to work hard to punch a hole in this pack, at a cost of only a few ounces.

Hipbelt Double-buckle System

I really like ULA’s “double-buckle” system on the hipbelt, which allows very precise, incremental tightening from four different angles and produces a snug, comfortable fit.

ula circuit hipbelt buckle

ULA’s double-buckle system allows for a perfect cinch on the hipbelt. Clay Bonnyman Evans photo.

ULA Circuit Cons

Side Pockets

The pockets are both deep and not-so-deep, cut on a diagonal from about 8 inches (front) to 11 inches (back), with a shock cord to batten things down. But 8 inches is just a tad too deep for me, and I found quick-drawing my water bottle required a bit more contortion than I’d prefer.

In addition, the “front” (i.e. the side you, the hiker, are on) of each side pocket is essentially open, attached by a small rivet on the bottom and stitches on top. This means you really shouldn’t store smaller items there: sunglasses, gloves, anything that might slip out.

Roll Top

I used to think cinch tops were ridiculous until I reviewed a pack that offered a cinch plus a roll-top, which for my money is the best combo (and, of course, will necessarily add a bit of weight). The roll-top here is fine, but you really do need to close it carefully and secure the top compression strap.


Though light for all it offers, the Circuit may be a few ounces heavier than weight-conscious hikers may prefer.


As I anticipated, I really love the ULA Circuit. I’m especially impressed by how tough the material is, considering the relatively light weight, the color (mine is a gorgeous royal blue) and all the exterior storage options — I’m a hiker who does not like “danglers,” so it’s nice to have somewhere to tuck things neatly away without opening the pack.

Having now given the Circuit a good test drive, I plan to take it when I return to the CDT this summer. I’ll be most interested to see if it really is as comfortable as my current favorite pack. One thing is for sure: it’ll be a lot tougher.

Shop the ULA Circuit

Comparable Packs

Featured image courtesy of Clay Bonnyman Evans.

The ULA Circuit was donated for purpose of review.

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Comments 3

  • Ryan : Jul 1st

    It’s worth noting the bag featured in all of these images appears to be the ULA Circuit featuring the X-Pac fabric customization option. It is not ULAs robic fabric (cheaper option, more durable, less water resistant). So your pack will not look like this standard off of the size. You can customize it for an additional fee to have x pac. I have one myself with xpac and it’s bombproof!

  • Jonathan Ward : Jul 15th

    I have the circuit and love it, but I don’t totally understand what the shock cords on the big stretchy pocket are for. To keep gear in the huge pocket from moving around? To strap stuff to the outside (wet clothes, etc.)? Gotta be some purpose that I dont know. But I love it. I have the current version, no mods.


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