Alpha One Niner Whitley Backpack vs Peak Design Outdoor Backpack 25L
The Alpha One Niner Whitley Backpack is 20L and 1.21kg2.7lb; the Peak Design Outdoor Backpack 25L is 20L and 1.2kg2.6lb. The Peak Design Outdoor Backpack 25L is 0.01kg0lb lighter. The Alpha One Niner Whitley Backpack costs $30 less. The Alpha One Niner Whitley Backpack fits the carry-on limit of 36 of 36 major airlines and the Peak Design Outdoor Backpack 25L fits 36; under the seat, 0 and 0 of 26.
| Spec | Alpha One Niner Whitley Backpack | Peak Design Outdoor Backpack 25L |
|---|---|---|
| Price | $219Best | $249 |
| Volume | 20L | 20L |
| Expands to | n/a | 25L |
| Weight | 1.21kg2.7lb | 1.2kg2.6lbBest |
| Carry-on compliance | 100% | 100% |
| Personal-item compliance | 0% | 0% |
| Dimensions | 47×27.9×15.2cm18.5×11×6in | 49×28×15cm19.5×11×6in |
| Laptop | 16" | 16" |
| Bottle pockets | n/a | 2 |
| Opening | main compartment zip, quick access zip behind carry handle | Roll-top, roll top + rear panel |
| Warranty | 5 years | Lifetime |
| Organizer | Yes | No |
| Shoe compartment | No | No |
| Hydration sleeve | No | Yes |
| Frame sheet | No | No |
| Water-resistant | No | Yes |
| Rain cover | No | No |
| MOLLE | No | No |
| Hip belt | No | No |
| Sternum strap | Removable | Yes |
| Load lifters | No | No |
| Shoulder strap | No | No |
| Luggage pass-through | Yes | No |
| Camera compartment | No | Insert sold separately |
| Bike-ready | No | No |
| Material | Dimension-Polyant X42, 500D or 1050D ballistic nylon with 200D Crimson Wave lining | Recycled Terra Shell 210D ripstop, PU coated (1500mm), PFAS-free water repellent |
| Last checked | 2026-09 | 2026-09 |
Where their airline fit differs
Both bags pass and fail the same airline size limits.
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Specs come from each brand's own product page. Fit uses listed dimensions in any orientation. How we score carry-on fit.