GEAR REVIEW: Ultralight Adventure Equipment Circuit Backpack


Here at Trail Lives, we absolutely love Cottage Gear Shops. Some of the best gear tested has come from these unlikely and relatively small companies, which are usually run by hikers like you and I. Founded in 2001 by a fellow thru hiker and located in Utah, Ultralight Adventure Equipment (ULA) offers some amazing ultralight gear, especially backpacks. Today, many consider ULA as cottage shop royalty, as their packs hold a standard of excellence by many long distance hikers. Within ULA packs, testers and ULA alike, report the Circuit as the most used on trail. I will be taking my ULA Circuit with my on my PCT Thru Hike this April.


1. Lightweight: Please don’t begrudge me the number I am about to say for my pack weight. I am 6′ 6” tall and thus my torso demands a much longer frame and thus a heavier pack. My height had something to do with me getting the Circuit. For a while, I struggled with packs that were just too small. I used the REI Flash 62 (large) for a while and

ULA Circuit. Large mesh pocket, and Shock Cord
Large mesh pocket, and Shock Cord

it would just ride up. My other pack, an Osprey Aether 75 fits me, but is too heavy for long distances where weight is limited. Here enters ULA, and their XL Circuit. Stripped down to my needs, it weighs 40oz (2 lb, 8oz). Yes, there

are lighter packs out there, but none that fit me as well as the Circuit does and I still dropped more than half a pound off my base weight switching to the Circuit. Finally, unlike other lighter packs, I can trust my Circuit to carry over 30 lb. easily. Check out this Gear List, to see how I kept a 10 lb. base weight using my Circuit.

Removable Features:

Roll Top Closure
Roll Top Closure
  • Hydration Sleeve (1.4 oz)
  • Internal Mesh Pocket (1.1 oz)
  • Water Bottle Holsters (0.8 oz)
  • Hand Loops (0.8 oz)
  • Single Aluminum Stay (2.0 oz)


Another tester at Trail Lives owns the Circuit in size medium and it weighs 34oz (2 lb. 2oz) on our scales (stripped down and modified).

2. Comfort: This might be the ULA Circuit’s best feature as it’s ride is the reason it is my go to pack. An easily adjustable hip belt slides up and down the back panel, giving you several inches of give in either direction. Velcro attaches the hip belt to the pack on both sides. The velcro is tough and I have never had a problem with it holding, despite adjusting the hip belt many times.

Side View
Side View

You can order different size hip belts depending on your body type. I use an XL frame, but a large hip belt. ULA also offers two types of shoulder straps; the standard J-Curve and an S-curved strap. The S-Curve is great for women, or men with a wider or more muscular chest and shoulders. I found the S-curve very comfortable but our other tester likes his standard J-Curve (5′ 10”, average build). Load lifters are one of the few ‘luxuries’ this pack affords, and the Circuit has very adjustable ones, which can slide back and forth along the shoulder strap, so they can lay on top of your shoulder, where ever that may fall. Finally, this pack can haul. I wouldn’t take it over 40 lb., and I wouldn’t really want to be near 40 lb. at all, but the Circuit will take me there. When I needed to carry a lot of water and food between a 150 mile resupply, my pack weight was around 34 lb. and I wasn’t burdened by it. This is all thanks to the 1.2 ounce Carbon Fiber suspension loop, a thick foam pad, and a single aluminum stay.

3. Durability: ULA uses their very own ULA 210 Robic fabric, which is three times harder to puncture than Dyneema, but still manages to stay at a light weight. You are getting a lot more durability per ounce of the fabric now, and it is noticeable. Both testers have bushwhacked through overgrown trails in New York’s Adirondack State Park without a problem. The fabric even allows a small amount of water resistance but this is more for mist and less for rain as the pack is nowhere near waterproof. I have hiked with my circuit around 600 miles and it still looks close to brand new, minus a few dirt stains here and there.

4. Space: For an ultralight pack, this thing has a lot of volume. The main body has 2900 cubic inches (47 liters) if you include the extension collar.

Back Panel, Adjustable Hip Belts
Back Panel, Adjustable Hip Belts

The front mess pocket adds another 400 cu in. (6L) and the side pockets another 700 cu in. (11L). Finally, two little hip belt pockets are great for snacks, a small camera, etc. All together the Circuit has 4,200 cubic inches of volume or about 68 liters of space. That is a lot of space!


1. Hot Back Panel: This is my biggest problem with the Circuit although it was limited to myself, as our other tester did not find it a problem. I run hot, with a normal body temp around 99.9 degrees, and I have never had much of a problem with the cold. If I am hiking or exercising, the cold really doesn’t exist. This is great when considering pack weight during the shoulder season and winter camping, but when it starts getting hot out, I start to sweat a lot. The Circuit’s back panel does not vent well, so if you are like me, prepare to sweat. This only really becomes a problem when you are really moving on particularly hot days. Our other tester who runs a little more middle of the field in terms of temperatures had a larger range of temperature before he began to sweat on his back, but eventually even he began to overheat on his back.

(note: This problem has never been serious enough to over power all the benefits of the Circuit for either tester.)

2. Accessibility: There is only one way into the circuit and that is through the top. The Circuit uses a roll top closure (like a dry bag) that rolls down depending on how much of the extension collar you are using.  This makes for getting in and out of your pack a little more time consuming than those with bottom zippers and/or front loading panels. It does get a little annoying to have to roll open the pack and then roll it closed every time you want something small from your pack.

4. Too much space: I am only putting this down here to play Devil’s Advocate. Every trip offers unique experiences and circumstances that will call for more or less space and load carrying ability. The Circuit is perfect for a long distance trek where versatility is needed more than the lightest possible pack weight. Both our testers found the joint 68 liters of volume more than necessary on a few shorter trips, while at the same time have praised its ability to carry more, if that problem presents itself, on those long trips where you need to adapt. So yes, you might not need all the space the circuit affords and thus you could go for a smaller, lighter pack.


I am taking the Ultralight Adventure Equipment Circuit with me on my Pacific Crest Trail Thru Hike. Both testers and Trail Lives ranks the Circuit as a top level ultralight pack and would trust it for anything from a weekend hike to a walk from Mexico to Canada. Talk to the people over at ULA for some of the best customer service you can only find from a small company run by fellow hikers.

2 thoughts on “GEAR REVIEW: Ultralight Adventure Equipment Circuit Backpack

  1. I found this review to be particularly helpful- thanks! As a tall hiker myself, I was very interested to read this because I’ve been considering the circuit for some time now! I think you may have sealed the deal for them.
    I’ve just come across this website, but I’m enjoying the content. Keep it up!

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s