50 Days Hiking with the Osprey Aether Pro 70

I've spent almost two months testing this tough midweight load hauler. Here are my impressions.

The Osprey Aether Pro weighs less than four pounds but has the weight and load-carrying capacity of a pack that normally weighs five to seven pounds. It’s become my go-to for guiding, big-game hunting, and spousal trips. (Photo: Andrew Skurka)
Andrew Skurka

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Recently, I looked through the photos of my Great Western Loop trip in 2007. My, my—I had such a small and light pack. But the trend has been moving in the wrong direction ever since, and for about a year I’ve been using the Osprey Aether Pro 70, a pack that has more volume and weighs more than anything I’ve worn since 2002.

I’ve used the Aether Pro for about 50 days, including on most of my guided trips for the past year, to an elk hunt in the Colorado Rockies in November, and on weighted training hikes in Boulder’s foothills. 

For women, Osprey offers the Ariel Pro 65, which has identical features and materials but a women’s-specific fit. Nearly all of my comments about the Aether are applicable to the Ariel as well.

Long-Term Review: Osprey Aether Pro 70 and Ariel Pro 65

The Aether/Ariel Pro will appeal most to backpackers who carry large or heavy loads that exceed the volume or load-carrying capacity of lightweight packs. These hikers want to be able to do this with a pack that weighs three to four pounds, rather than the normal five to seven. When I’m leading clients, hauling out elk quarters, or carrying most of the food and gear on a group trip, the Aether Pro has become my go-to backpack. I think Osprey also imagined it being used for mountaineering expeditions and adventurous long-distance hikes (think: thru-hiking Alaska’s Brooks Range), and I’d agree with that thinking.  

My sole criticism of the Aether/Ariel Pro is its external storage. Instead of having the removable compartments located in the wedge between the hipbelt and main compartment, I’d rather have conventional side and hipbelt pockets, plus a shoulder-strap pocket. But I’ve overlooked this shortcoming because of its performance otherwise.

Andrew Skurka
Spousal trip in Utah’s Cedar Mesa, when I carried just about everything for the two of us—plus what seemed liked a lot more. (Photo: Andrew Skurka)

Key Specs

  • Volume: 70 liters in size medium for the Aether, 65 liters for the Ariel
  • Strong and durable fabrics throughout
  • Stiff aluminum peripheral frame and a single aluminum center stay
  • Mesh-covered aerated foam back panel
  • Heat-moldable foam hipbelt
  • Two front compression or attachment straps
  • Attachment points for trekking poles, two ice tools, a hydration reservoir, and a sleeping pad
  • $375 MSRP
  • More information (men’s, women’s)

The spec weight of the Aether Pro is 3 pounds 15 ounces. Mine weighs 4 pounds 1.9 ounces. Its weight can be further reduced by removing features, such as:

  • The floating top lid (5.1 ounces)
  • Two side compression straps (0.5 ounces each, or 1.0 ounce total)
  • A zippered side pocket (2.7 ounces)
  • A cinchable side pocket (2.6 ounces)

The total weight of these removable items is 11.4 ounces, which would reduce the spec pack weight to 3 pounds 3.6 ounces, but at the cost of some functionality.


To help you decide if the Aether/Ariel Pro is right for you, comparing it to other packs is probably useful.

The Aether Pro Versus the Aether AG

The Aether/Ariel Pro was new for spring 2018 and is essentially a stripped-down version of the Aether AG (Anti-Gravity).

Compared to the AG, the Pro:

  • Uses more premium fabrics
  • Has a simpler harness system that’s lighter and probably carries better but is less ventilated
  • Weighs 1.3 pounds less, with an opportunity to shed extra weight by removing features
  • Costs $65 more ($375 versus $310 for the 70-liter version of the AG)

Overall, I think the Pro is the better value. The only feature of the AG’s that I wish it had are the external pockets.

The Aether Pro Versus “Sweet Spot” Packs

My pack recommendation for most backpackers is a 2.5-pound framed pack that is nicely featured, made of durable materials, and costs $200 to $300, like the Osprey Exos, Sierra Designs Flex Capacitor, and ULA Circuit. Such models are ideal for standard thru-hikes and high routes and for backcountry trips of up to ten days.

If your plans are more exceptional and require a pack with more volume or greater load-carrying capabilities, plus some additional durability, the Aether/Ariel is worth a look.

The Aether Pro Versus Deuter, Gregory, and Mystery Ranch

Other packs match (and may exceed) the volume and load-carrying capacity of the Aether Pro, including the Deuter Aircontact 65 + 10, Gregory Denali 75, and Mystery Ranch Glacier. But none of them rival its sub-four-pound weight. In size medium, the Denali weighs six pounds three ounces; the Aircontact, five pounds six ounces; the Glacier, five pounds ten ounces.

The Aether Pro Versus Seek Outside’s Divide and Unaweep

The most direct comparisons to the Osprey Aether/Ariel Pro may come from the backpack-hunting industry, which is presented with similar volume and load demands. I’m specifically thinking of the Divide 4500 and Unaweep 4800 from Seek Outside. Both packs weigh in the low to mid three pounds and approach $400. 

Andrew Skurka
This pack display from a guided trip in Rocky Mountain National Park puts the Osprey Aether Pro in perfect context. From left to right: I’m carrying it, but my clients have the Flex Capacitor, MTC Jam, and Osprey Levity. Note that all of our packs are nearly empty in this photo, since we did a day hike from a base camp on day two to help acclimatize. (Photo: Andrew Manalo)

Suspension and Harness

The standout feature of the Aether/Ariel is its suspension. Simply put, this pack is designed to haul weight. It’s light-years better than the Exos and even in a different league than the Flex Capacitor, which is considered to carry weight better than most sub-three-pound packs.

The peripheral frame, made of 7075 tubular aluminum, is extremely stiff, so it efficiently transfers weight. As I’ve come to expect of Osprey, the harness system is masterfully fitted, and the weight is distributed well across the hipbelt, shoulder straps, and back panel, which have generous yet firm cushioning.

On overnight trips, I regularly have carried loads in the 40-pound range, and on recent training hikes I’ve carried exactly 50 pounds. I will never say that carrying 50 pounds is comfortable, but some packs do it more gracefully than others, and the Aether/Ariel is among them.

Andrew Skurka
On a recent training hike in Boulder’s foothills, wearing the Black Diamond Rhythm Tee and carrying the Osprey Aether Pro 70 pack, loaded with 50 pounds. (Photo: Andrew Skurka)

To achieve this load-carrying performance in a sub-four-pound pack, Osprey gave the Aether Pro a more conventional back panel, abandoning the ventilated trampoline that you’ll find on the Aether AG and Exos. The mesh-covered aerated foam (branded as AirScape) provides relatively little ventilation in reality, so you should expect perspiration to build up on warm days and during hard efforts.

Andrew Skurka
The aerated back panel does little to reduce perspiration buildup in warmer conditions and during hard efforts, as evidenced by the sweat line. But a more ventilated back panel would add weight and expense and compromise the load stability. (Photo: Andrew Skurka)


The Aether Pro is is made with four types of fabric:

  • The main body is 210-denier nylon and 200-denier ultra-high-molecular-weight polyethylene (UHMWPE)
  • The bottom is 200-denier UHMWPE
  • The accent is 315hd oxford
  • The trim isn’t specified but appears to be a 200-denier-ish nylon

UHMWPE is the source material for Dyneema and Spectra fibers. Osprey chose nonbranded UHMWPE fabrics presumably as a cost-savings measure. Sierra Designs made the same decision with the Flex Capacitor.

While writing this review, I inspected my pack for wear and found no abrasions or tears. The Aether/Ariel seems like it’s built for a lifetime of use. If this proves not to be the case, it’s covered under Osprey’s All Mighty Guarantee.

Andrew Skurka
The four fabrics: 210×200 [[is this dimension referring to inches?]] gridstop body, 200-denier Chineema bottom, 315-denier oxford accent, and an unspecified 200-denier-ish trim. (Photo: Andrew Skurka)


The main compartment is tall and narrow, even before the extension collar is utilized. I believe this shape leads to better load stability, but it’s disappointing that a full-size bear canister cannot be stored horizontally in the Aether. Shelters and hammocks without intentionally short pole sets will have to be placed vertically, too.

External Storage

The floating top lid is nicely sized and is convenient for items that you occasionally need during the day, such as toiletries, snacks, extra water, and even a wind shirt or minimalist rainjacket. If you don’t need its volume or wish to pare five ounces from the pack, the lid can be easily removed.

As I mentioned above, the hipbelt and side pockets are underwhelming, and I consider them to be the Aether’s most notable imperfection. I believe it’s essential to have quick access to oft-needed items like water, a camera or phone, maps, lip balm, sunscreen, insect repellent, a head net, water purification, and other items. The design of hipbelt pockets and side pockets is vitally important—they must be accessible, secure, and generous.

To their credit, the hipbelt and side pockets are easily accessible, and one can be zippered shut. But their total volume is marginally acceptable, and the cinchable pocket is only deep enough for a one-liter Nalgene. Using a one-liter Smartwater bottle (which weighs 2.4 ounces less) is impractical—it immediately slips out if you lean forward to pick up a trekking pole or step under a downed tree.

I appreciate that Osprey tried something different here, but personally, I would have preferred the Aether AG design, which includes two permanent side pockets and two permanent hipbelt pockets.

Andrew Skurka
Only a one-liter Nalgene can be used with the cinchable side pocket. A one-liter Smartwater bottle slips out easily. (Photo: Andrew Skurka)

Compression and Utility

The Aether/Ariel Pro has two sets of compression straps:

  • Two horizontal straps across the front
  • One Z-style removable strap on each side

In addition to stabilizing the load, these straps are useful for securing trekking poles, an umbrella, ice tools, and long tent poles. Skis could be attached, too, but I’d want to protect the pack fabric from the metal edges first.

The side compression straps photograph well, but the webbing does not slide easily through the rectangular sliders. O-rings would have been a better choice.

Andrew Skurka
External attachments and utility is mostly excellent. I would only recommend that the hardware on the removeable side straps be changed to an O-ring, to improve glide. (Photo: Andrew Skurka)

Aether Pro 70 Ariel Pro 65

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Lead Photo: Andrew Skurka
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