ULA Circuit vs ULA Catalyst
Quick take: The ULA Circuit costs $20 less; the ULA Catalyst carries more (75 vs 68 liters); the ULA Circuit is lighter (2.41 vs 2.78 lbs).
Which one to buy
The clearest advice on this pair: buyers who don't need the extra volume usually end up wishing they'd bought the Circuit. The two ULA packs share the same DNA, the same 400-denier Robic, the same hoop frame, the same four fixed torso sizes and the same lifetime warranty. For $20 more and a few ounces, the Catalyst adds 7 L, a second stay and a 40 lb rating against the Circuit's 35.
The Circuit is the right pack for most thru-hikers. Its 35 lb rating is honest, its 68 L takes a BV500 plus a week of food, and owners routinely report its Robic lasting 3,000-5,000 trail miles before meaningful wear. Heavy-kit hikers should look at the Catalyst, and that's the line: if your loads stay at or under 35 lb, the Circuit carries them well.
The Catalyst earns its place on trips that outgrow that: 8-10 day food carries, winter kit, or a canister plus a packraft. Its dual stays keep it composed where single-stay packs fold, with desert hikers carrying 8 liters of water without collapse, and a BV500 fits horizontally with about 10 days of food. The cost shows on lighter trips, where the big collar gets floppy and needs constant compression.
Both share ULA's known trade-offs. The foam backs have zero ventilation and soak a shirt on humid climbs, sizing is direct-order only, so measure carefully, and Circuit owners add that the J-curve shoulder straps don't suit every chest and lead times stretch in thru-hiking season.
ULA Circuit
For most thru-hikers and three-season backpackers whose loads stay at or under 35 lb, including Sierra canister trips with a week of food.
ULA Catalyst
Worth the extra $20 if you regularly carry 8-10 days of food, winter kit or a packraft and need a 40 lb frame.
| Spec | ULA Circuit | ULA Catalyst |
|---|---|---|
| Price | $299.99 | $319.99 |
| Rating | — | — |
| Type | Ultralight Pack | Ultralight Pack |
| Frame Type | Internal Frame | Internal Frame |
| Capacity | 68 L | 75 L |
| Weight | 2.41 lbs | 2.78 lbs |
| Max Load | 35 lbs | 40 lbs |
| Torso Fit | S 15-18 in, M 18-21 in, L 21-24 in, XL 24+ in | S 15-18 in, M 18-21 in, L 21-24 in, XL 24+ in |
| Material | Robic 400 nylon | ULA 400 Robic nylon |
| Back Panel | Foam panel with carbon-fiberglass hoop and internal stay | Foam panel with carbon-fiberglass hoop and dual stays |
| Adjustable torso | No | No |
| Ventilated back | No | No |
| Raincover included | No | No |
| Hipbelt pockets | Yes | Yes |
| Removable lid | No | No |
| Hydration sleeve | Yes | Yes |
| Fits BV500 bear can | Yes | Yes |
| Warranty | ULA lifetime warranty: original owner, defects in materials and workmanship (wear, accidents and misuse excluded) | ULA lifetime warranty: original owner, defects in materials and workmanship (wear, accidents and misuse excluded) |
Pros & cons
ULA Circuit
- ✓Has topped the Halfway Anywhere PCT gear survey for years — no pack has more verified thru-hiking miles behind its reputation.
- ✓Owners routinely report 3,000-5,000 trail miles before meaningful wear; the 400d Robic build is the UL durability benchmark.
- ✓The 68L total volume (bag plus huge pockets) swallows a BV500 plus a week of food, which smaller UL packs can't.
- ✓Carries its full 35 lb rating honestly — the hoop-and-stay frame outperforms most packs in its weight class.
- ✓The giant mesh front pocket and dual oversized hipbelt pockets define the category's organization standard.
- ✓Hand-made in Utah with a service team famous for repairs, spare parts, and straight answers.
- ✓The roll-top plus Y-strap handles bear canisters, foam pads, and packrafts without drama.
- ✓Resale value is exceptional — used Circuits sell within hours on UL trade forums.
- ✗The foam back panel has zero ventilation; expect a soaked shirt on humid climbs.
- ✗Fixed torso sizing means no adjustment range — measure carefully before ordering.
- ✗The utilitarian look (and famously loud color options) is a running joke even among loyalists.
- ✗At 2.41 lbs it's now heavier than newer rivals like the Kakwa 55 that match its carry.
- ✗No lid and minimal internal organization — everything lives in stuff sacks or the main tube.
- ✗Direct-order only in the US; you can't try one on in a store.
- ✗Lead times stretch during thru-hiking season, sometimes badly.
- ✗The J-curve shoulder straps don't suit every chest shape; some switch to S-straps aftermarket.
ULA Catalyst
- ✓The go-to answer when ultralight hikers ask 'what if I need more than a Circuit' — same DNA, more capacity, 5 lb higher rating.
- ✓Dual aluminum stays plus the hoop make its 40 lb rating honest; desert hikers carry 8L of water without collapse.
- ✓75 liters swallows a BV500 horizontally plus 10 days of food — the specific use case owners buy it for.
- ✓The same 400d Robic bombproof reputation as the Circuit, with thousands-of-miles reports common.
- ✓Massive front mesh and hipbelt pockets keep a full day's needs outside the main bag.
- ✓Hand-made in Utah, easily repairable, backed by ULA's excellent service.
- ✓About 6 ounces heavier than the Circuit for 7 more liters and a stiffer frame.
- ✓Strong resale on trade forums, like everything ULA.
- ✗Overkill for standard three-season loads — most buyers who don't need the volume end up wishing they'd bought the Circuit.
- ✗Same zero-ventilation foam back as the Circuit; sweat is the tax.
- ✗Fixed torso sizes with direct-order-only sizing risk.
- ✗At 2.78 lbs it's approaching crossover packs with plusher harnesses.
- ✗The big collar is floppy when underfilled, so partial loads need diligent compression.
- ✗No lid, no internal organization — the usual ULA minimalism.
- ✗Seasonal lead times can be long.
- ✗The look is pure function; nobody buys a Catalyst for style.
ULA Circuit vs ULA Catalyst: common questions
Should I buy the Catalyst just in case I need the extra room?▾
No. Buyers who don't need the volume usually wish they'd bought the Circuit, because the bigger collar gets floppy when the pack is underfilled. Buy the Catalyst for trips that already need it.
Can the Circuit handle a bear canister, or do I need the Catalyst?▾
The Circuit handles it. Its 68 L takes a BV500 plus a week of food, and the roll-top and Y-strap can hold a canister on top when the bag is full. The Catalyst adds room for about 10 days of food around the canister.
Is the Catalyst's 40 lb rating worth it over the Circuit's 35?▾
If you carry heavy water or long food loads, yes. Its dual stays keep it composed where single-stay packs fold. The Circuit's 35 lb rating is honest, but it isn't a hauler beyond that.