Osprey Aura AG 50L Women's Backpacking Backpack vs REI Co-op REI Flash 55 Women's Backpacking Backpack

Editorial Team
Last modified at July 22, 2026
Choosing the right backpacking backpack can significantly enhance your outdoor experience. Both the Osprey Aura AG 50L and the REI Flash 55 are designed specifically for women, offering unique features that cater to different needs and preferences.

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Osprey Aura AG 50L Women's Backpacking BackpackREI Co-op REI Flash 55 Women's Backpacking Backpack
Osprey Aura AG 50L Women's Backpacking Backpack
REI Flash 55 Women's Backpacking Backpack
Capacity

WXS/S: 47 L; WM/L: 50 L

XS: 53 L; XS torso/M hipbelt: 54 L; S: 55 L; M: 57 L

Weight

WXS/S: 4 lb 4 oz; WM/L: 4 lb 5 oz

XS: 2 lb 10 oz XS Torso x M Hipbelt: 2 lb 11 oz S: 2 lb 11 oz M: 2 lb 12 oz

Torso Adjustability

WXS/S: 13–17 in; WM/L: 16–20 in

XS: 15–17 in XS Torso x M Hipbelt: 15–17 in S: 16–18 in M: 17–19 in

Hip Belt Size Range

26-29.5 in
26-35 in
29.5-35 in
35-41 in

XS: 30–38 in XS Torso x M Hipbelt: 34–44 in S: 32–40 in M: 34–44 in

Hydration Compatibility

Internal hydration reservoir sleeve with center back exit port

Yes

Warranty

All Mighty Guarantee

REI satisfaction guarantee: one year for members

Trekking Pole Attachment

Stow-on-the-Go trekking pole attachment system

Yes

Rain Cover Compatibility

Included raincover made with PFC/PFAS-free DWR and bluesign® approved materials

Compatible; not included

Side Pockets

Tall dual-access side water bottle pockets

Yes

Hip Pockets

Dual zippered hipbelt pockets

Yes

Sternum Strap

Adjustable sternum strap with whistle

Yes

Load Lifters

Yes

Yes

Sleeping Bag Compartment

Zippered sleeping bag compartment with removable divider

No separate compartment

Comfort

Osprey Aura AG 50L Women's Backpacking Backpack

4.6/ 5.0

REI Flash 55 Women's Backpacking Backpack

4.8/ 5.0

Comfort is crucial for backpacking backpacks as it directly impacts your ability to enjoy long hikes without discomfort. A more comfortable backpack can make a significant difference, especially on multi-day trips where you'll be carrying a lot of weight. The REI Flash 55 excels in comfort with its cushioned shoulder straps and padded hip belt, which are consistently praised by users. The Osprey Aura AG 50L also offers good comfort with its Anti-Gravity suspension system, but it falls slightly short compared to the REI Flash 55. The REI Flash 55's design ensures that it doesn't create hot spots or rub marks, making it a better choice for those who prioritize comfort.

Fit

Osprey Aura AG 50L Women's Backpacking Backpack

3.6/ 5.0

REI Flash 55 Women's Backpacking Backpack

4.1/ 5.0

A good fit ensures that the backpack sits well on your body, distributing weight evenly and reducing strain. The REI Flash 55 offers a more customizable fit with its adjustable shoulder harness and hip belt size, accommodating a wider range of body types. The Osprey Aura AG 50L is also designed to fit well but has fewer adjustable features. The REI Flash 55's fit is praised for being versatile and accommodating different sizes, making it a better option for those who struggle to find a well-fitting backpack.

Load Transfer

Osprey Aura AG 50L Women's Backpacking Backpack

3.4/ 5.0

REI Flash 55 Women's Backpacking Backpack

4.6/ 5.0

Effective load transfer is essential for reducing strain on your shoulders and back, making it easier to carry heavy loads over long distances. The REI Flash 55 excels in this category, with users praising its ability to carry up to 40 lbs comfortably. The Osprey Aura AG 50L also performs well but has some issues with the hip belt not holding the bag in place, which can cause discomfort. The REI Flash 55's wraparound hip belt and stiff foam make it a better choice for those who need to carry heavy loads.

Ventilation

Osprey Aura AG 50L Women's Backpacking Backpack

3.1/ 5.0

REI Flash 55 Women's Backpacking Backpack

4.2/ 5.0

Good ventilation helps keep your back cool and dry, reducing sweat and discomfort during long hikes. The REI Flash 55 has better ventilation with its mesh material that allows for breathability, keeping your back cool even in hot conditions. The Osprey Aura AG 50L has mixed reviews on ventilation, with some users finding it adequate while others experience chafing and rubbing. The REI Flash 55's ventilation is a clear advantage for those who hike in warm climates.

Organization

Osprey Aura AG 50L Women's Backpacking Backpack

3.9/ 5.0

REI Flash 55 Women's Backpacking Backpack

4.4/ 5.0

Organization is key for keeping your gear accessible and well-arranged, making it easier to find what you need without digging through your pack. The REI Flash 55 offers excellent organization with its multiple pockets, compression straps, and modularity, allowing you to customize the pack to your needs. The Osprey Aura AG 50L also has good organization features, including a detachable lid and various pockets, but it falls slightly short compared to the REI Flash 55. The REI Flash 55's organization features make it a better choice for those who need to keep their gear well-organized and easily accessible.

Accessibility

Osprey Aura AG 50L Women's Backpacking Backpack

3.7/ 5.0

REI Flash 55 Women's Backpacking Backpack

4.8/ 5.0

Easy access to your gear can save time and effort, especially when you need to grab something quickly without stopping. The REI Flash 55 excels in accessibility with its easy-access water bottle pockets, hip belt pockets, and one-hand zipper operation. The Osprey Aura AG 50L also offers good accessibility features, but it doesn't match the convenience of the REI Flash 55. The REI Flash 55's accessibility features make it a better choice for those who need quick and easy access to their gear.

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Conclusion & Final Verdict:

After comparing the Osprey Aura AG 50L and the REI Flash 55, it's clear that both backpacks have their strengths. The REI Flash 55 stands out for its superior comfort, fit, load transfer, ventilation, organization, and accessibility. It's an excellent choice for those who prioritize ease of use and comfort on long hikes. On the other hand, the Osprey Aura AG 50L offers better organization and includes a rain cover, making it a good option for those who need to keep their gear well-organized and protected from the elements. Ultimately, the best choice depends on your specific needs and preferences.

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