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Sixth Blog Post

Sep 14, 2024

There’s a lot to consider when choosing the right pack for your next adventure. Two key factors are: How much total weight will you be carrying (Gear + Consumables)? And what kind of gear do you need? Is it bulky winter gear, or will you need a bear canister? After that information has been gathered the next question is “Well, what pack do I need?” Which inevitably leads to either the Circuit, Circuit SV, or the Catalyst. The Circuit SV is identical to the standard Circuit in features, it’s just a smaller, 48L version.

It’s a tough choice, we get it.

Not only are the Catalyst and the Circuit our two most popular packs, they are also two of the most popular backpacks amongst thru-hikers according to the Halfway Anywhere Thru-hiker Survey.

Whether you’re packing for unpredictable weather or tackling long stretches without water or resupply, having the right gear is crucial for success in the backcountry. The goal of this article is a detailed comparison of the Catalyst and Circuit, focusing on key areas such as capacity, weight, framing systems, and pack features.

Pack Comparison: ULA Circuit vs. ULA Catalyst

Capacity and Volume

Getting a backpack just to have to switch it out mid-trip is a hassle. We recommend buying your backpack last after you’ve collected all of your other gear. You can use a cardboard box to measure the volume of all your gear and then translate the size of that box to cubic inches or liters to determine what pack size you’ll need. Measure only the gear you’ll carry inside of the pack.

ULA Catalyst

Total Capacity: 75 liters
Main Compartment: 43 liters
Max Carrying Capacity: 40 lbs
Target Use: Thru-hiking, Large Water and Food Carries, Section Hiking, Winter Backpacking, Bear Canister Carries, Hiking Guides and anyone that carries extra gear for their backpacking partner.

ULA Circuit

Total Capacity: 68 liters
Main Compartment: 39 liters
Max Carrying Capacity: 35 lbs
Target Use: Thru-hiking, Bear Canister Carries, Section Hiking, Weekend Trips.

ULA Circuit SV

Total Capacity: 48 liters
Main Compartment: 37 liters
Max Carrying Capacity: 35 lbs
Target Use: Thru-hiking, Bear Canister Carries, Section Hiking, Weekend Trips.

The Catalyst is the largest pack in our line-up and is most utilized by hikers with long stretches between resupply points and heavier loadouts. The Catalyst was designed for carrying a bit more gear, food, or clothing. Its total capacity makes it an ideal choice for longer trips where resupply points are farther apart, like desert sections on the Continental Divide Trail or Pacific Crest Trail. The season you’re considering also comes into play with choosing your pack; hiking in colder weather requires bulkier clothing and gear. Bear country more commonly requires bear canisters and the Catalyst can fit canisters as large as the BV500 horizontally inside of the pack. All of this can add up to be more gear than some other packs can handle comfortably.

The Circuit is smaller than the Catalyst but still offers plenty of volume for multi-day trips. It’s perfect for hikers who have dialed in their gear and don’t need the extra space the Catalyst provides. The Circuit can fit bear canisters as large as the BV500 vertically inside of the pack. The Circuit has been the most popular pack on the Pacific Crest Trail for multiple years in a row and is a perfect blend of a lightweight pack that’s sturdy enough for the demands of a thru-hike.

The Circuit SV is the smallest framed pack in our line-up. Piggybacking off the features of the 68L Circuit, the Circuit SV offers all the robust support and functionality you’d expect from us here at ULA, just in a more compact package. The Circuit SV is for anyone who finds their current Circuit a little too big post thru-hike, and wants a bag that’s built for smaller contemporary gear. than the Catalyst but still offers plenty of volume for multi-day trips. The Circuit SV can fit bear canisters as large as the BV500 vertically inside of the pack. If you want a reliable light-weight pack for multi-day trips, the Circuit SV is a great option.

Shared features

Both the Catalyst and Circuit offer numerous features and external storage options to help keep your gear where you need it:

Height Adjustable Hip-belt with Pockets: All three packs come with spacious, easily accessible hip-belt pockets for small essentials like snacks, phone, or GPS devices. The hip belts on these packs are removable and height adjustable allowing you to get a more precise torso fit.
Side Pockets: The Catalyst, Circuit, and Circuit SV both feature large cinchable side pockets that can easily fit two 1L Smartwater bottles. The Catalyst pockets are a little bit taller than the Circuit and SV side pockets but they both fit the same diameter.
Shock Cord and Compression Straps: All models come with shock cord and top + side compression straps to keep smaller loads stable.
Mesh Dorsal Pocket: All packs feature a dorsal pocket made up of UltraStretch mesh material.
Load Lifters: All packs feature load lifters that enable you to bring heavier loadouts closer to your body.
Contoured Shoulder Straps: All three are offered in our “S” and “J” style shoulder straps with adjustable sternum strap.
Hydration Ports: All packs in the Ripstop Robic Nylon version feature hydration ports to use with a water bladder system.
Stash Pocket Compatible: All packs are compatible with our internal stash pocket and water bladder pocket.
Removable Straps System: All Circuit, Circuit SV, and Catalyst models built in 2024 or after are compatible with our removable Top Y-strap and removable Bottom Strap systems.
Top-loading Design: All packs have a classic top-loading design with a roll-top closure for easy access.
Ice-axe/Trekking Pole Loops: All packs feature two points of attachment for ice-axes and trekking poles. A fixed bottom webbing loop holds the ice-axe head in place while a cinchable section of shock cord fastens the handle to the pack near the top of the dorsal pocket.

Removable bottom straps and ice loop

Frame stay and delrin loop on The Circuit

Twin frame stays on The Catalyst

Bear Canisters

Both the Catalyst and the Circuit can fit food storage bins like the BV500 and under. The Catalyst can fit a BV500 horizontally, while the Circuit fits it vertically.

ULA Circuit + Circuit SV

Internal Carrying: Canisters as large as a BV500 can comfortably fit vertically inside of the pack.
External Carrying: If your gear is taking up a majority of the space inside of your pack and the bear canister cannot fit, then we recommend the removable Top Y-Strap attachment in order to properly secure your bear canister to the top of your pack.

ULA Catalyst

Internal Carrying: Canisters as large as a BV500 can fit both vertically and horizontally inside of the pack. We recommend putting your canister in horizontally to get the best fit for your gear.
External Carrying: With a pack as large as the Catalyst you’re not as likely to fill up the pack with gear, but if you need to carry a canister on the outside of the pack, we recommend the removable top Y-strap attachment.

Final Thoughts

Both the Catalyst, Circuit, and Circuit SV are fantastic options for any serious backpacker, offering a great blend of comfort, weight savings, and durability. The Catalyst is better suited for those who need more carrying capacity and plan on longer, more demanding trips where they anticipate a total pack weight that is between 35 and 40 lbs or want to carry a bear canister horizontally inside of the pack. The Circuit or Circuit SV, on the other hand, is perfect for ultralight enthusiasts who want to streamline their gear for shorter or less gear-intensive hikes. If you know your total pack weight won’t be over 35 lbs, the Circuit will save you nearly half a pound over the Catalyst!