ULA Circuit vs REI Co-op Flash Air 50
Quick take: The REI Co-op Flash Air 50 costs $1 less; the ULA Circuit carries more (68 vs 50 liters); the REI Co-op Flash Air 50 is lighter (2 vs 2.47 lbs).
| Spec | ULA Circuit | REI Co-op Flash Air 50 |
|---|---|---|
| Price | $300 | $299 |
| Rating | — | 4.1★ (49) |
| Type | Ultralight Pack | Ultralight Pack |
| Frame Type | Internal Frame | Internal Frame |
| Capacity | 68 L | 50 L |
| Weight | 2.47 lbs | 2.0 lbs |
| Max Load | 35 lbs | Not specified by the manufacturer |
| Torso Fit | S: 15-18 in, M: 18-21 in, L: 21-24 in | See manufacturer sizing |
| Material | Robic 400 nylon | UHMWPE ripstop nylon |
| Back Panel | Foam panel with carbon-fiberglass hoop and internal stay | Spring steel stays with foam padded back |
| Adjustable torso | No | No |
| Ventilated back | No | No |
| Raincover included | No | No |
| Hipbelt pockets | Yes | Yes |
| Removable lid | No | No |
| Hydration sleeve | Yes | No |
| Fits BV500 bear can | Yes | No |
| Warranty | ULA lifetime against defects | Manufacturer warranty; terms not published |
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 2.33 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.
REI Co-op Flash Air 50
- ✓Backed by REI's return policy, which is uniquely valuable in a segment where most packs are made to order.
- ✓A shaped spring steel frame flexes and returns rather than taking a set like aluminium stays.
- ✓UHMWPE ripstop gives gridstop-style tear resistance.
- ✓32 oz for 50 L is competitive with cottage packs at similar prices.
- ✓Available to try on in person at REI stores, which no cottage pack is.
- ✓$299 sits mid-range for the segment.
- ✓Foam padded back adds comfort the minimalist packs omit.
- ✓Hipbelt pockets included.
- ✗No published maximum load figure.
- ✗Heavier than the Bonfus Framus while carrying 8 L less.
- ✗Spring steel frames can deform permanently if badly overloaded.
- ✗No adjustable torso.
- ✗Not waterproof, unlike the Ultra-fabric packs at this price.
- ✗REI's ultralight design heritage is shorter than the cottage brands'.
- ✗Fewer configuration options than a made-to-order pack.
- ✗50 L is tight for a bear canister plus a long food carry.