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Elemental Horizons Aquilo Backpack Review

The Aquilo is the mouse that roared. I expected it to be a smaller frameless backpack based on its specifications, but it jumped into the high volume pack category, then it came out on top in that group.

Hightly Recommended

Overall Rating: Highly Recommended

I tested a pre-production version of the Aquilo that had a few surprises and shortcomings. However, the production model promises to alleviate the issues I have. The important thing to recognize is that the Aquilo is not a smaller volume pack for ultralight backpacking; it is in fact a larger volume pack for lightweight backpacking, and a good one at that. The issues I bring up in this review have been corrected in the production pack, which I have seen, so I have nothing left to complain about. The Aquilo is superbly constructed, a very capable load hauler, and a flawless design, so it deserves our Highly Recommended rating.

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by Will Rietveld |


Elemental Horizons Aquilo Backpack Review - 1
Elemental Horizons Aquilo on a summer backpack in the southern Rockies. The newly introduced Aquilo has a removable contoured tubular aluminum stay, plenty of volume, and an excellent compression system.

Elemental Horizons, founded by Matthew Lagas-Rivera, is a new, small company offering lightweight backpacks and accessories. The Aquilo is a frameless backpack with an available contoured aluminum tubular stay. At 31.5 ounces (893 g), the Aquilo weighs twice as much as the lightest frameless backpacks I tested for our Frameless Backpack State of the Market Report 2011, but for lightweight backpacking, where the Aquilo properly fits, its weight, suspension system, features, and load carrying capability are impressive.


Year/Model 2011 Elemental Horizons Aquilo (
Style Top loading frameless backpack with removable stay system, drybag closure with two side straps and one top compression strap
Volume Size Large tested.
Specified volume: 3200 cubic inches (52 L)
Measured volume: 4090 cubic inches (67 L), includes pockets and extension collar
Weight Measured weight: 29.5 oz (836 g) without stay or accessories, 34.1 oz (967g) with stay
Manufacturer specification: 31.5 oz (893 g) size M for latest version
Sizes Available Unisex S, M, L
Fabrics Pack body and pockets are 70d 1.9 oz/yd2 (64 g/m2) urethane coated ripstop nylon; bottom and reinforcements are 420d urethane coated diamond ripstop nylon; 7 oz/yd2 (237 g/m2) spacer mesh on hipbelt, backpanel, and shoulder straps
Features Sternum strap with whistle buckle, frontpanel bungie system, full height fabric front pocket with elastic binding, four fabric side pockets with drawcord closure, three compression straps each side, 12-in (30-cm) extension collar, drybag type top closure with one top compression strap, one ice axe loop, haul loop, interior zippered stash pocket, removable inside backpanel foam pad/sit pad, load lifters, hipbelt stabilizer straps, center pull hipbelt tightening
Volume to Weight Ratio 139 in3/oz (based on 4090 in3 and measured weight of 29.5 oz (size Large)
Maximum Comfortable Load Carrying Capacity 30 lb (13.6 kg) estimated comfortable load for an average person carrying the pack all day
Carry Load to Pack Weight Ratio 14.1 (based on 30 lb and a measured weight of 2.13 lb with stay)
Options Contoured tubular aluminum stay, three hipbelt sizes, hipbelt pockets, shoulder strap water bottle pouch


First things first; although the Aquilo is specified at 2700 cubic inches (44.2 L) for size Medium and 3200 cubic inches (52 L) for size Large (which I tested), I measured the actual volume of the Aquilo (size Large) to be a whopping 4090 cubic inches (67 L), which is 28% larger than specified. Matthew later mentioned that the specified volume is for the main compartment only. The key point here is that the Aquilo is a large volume frameless backpack, well suited for lightweight backpacking, but it has way too much volume for ultralight backpacking. I would love to see a smaller version of this pack for ultralight backpacking.

Elemental Horizons Aquilo Backpack Review - 2
Views of the production Elemental Horizons Aquilo pack: The frontpanel (far left) has a tall fabric front pocket and bungie attachment system. The backpanel (photo 2) is 3D mesh and has a removable foam pad inside the pack. Each side (photo 3) has two fabric pockets (a tall pocket and a short one) and three compression straps. The pack’s top (far right) has a drybag type closure with two side straps and one top strap (not two as shown).

Elemental Horizons Aquilo Backpack Review - 3
Suspension system: The Aquilo has an available contoured tubular aluminum stay (left) that slides into sleeves on the inside of the backpanel and anchors to the hipbelt. The flap that holds the stay in place has a zippered stash pocket. The pack’s suspension system (right) is sturdy, well padded, and has load lifters and hipbelt stabilizers. Much of the Aquilo’s weight is padding in the backpanel, shoulder straps, and hipbelt.

Elemental Horizons Aquilo Backpack Review - 4
Features: The Aquilo has a huge nearly full height fabric front pocket (left) and the current model has two side pockets on each side (center) instead of one as shown. Useful accessories are hipbelt pockets (shown below) that are available in two sizes, and a shoulder strap water bottle holder (right).


Elemental Horizons Aquilo Backpack Review - 5
This photo shows the main issue I had with the Aquilo - the pack has much more volume than specified, so my gear kit filled only about half of the available volume. The pack is compressed as much as it will go and I still could not fill it up. (Note: the current version of the pack has three compression straps on each side, which should eliminate the bulge.) I was trying to use the Aquilo for ultralight backpacking, since I understood at the time that its volume is 3200 cubic inches (52 L). I later measured the volume at 4090 cubic inches (67 L).

As shown in the photo, even with the pack’s compression system fully tightened, the pack still has too much volume for my ultralight gear kit. With the main compartment partially full, the pack’s top closure straps don’t work very well (they slip), and I had to criss-cross them to tighten the top down.

I finally measured the Aquilo’s actual volume as part of my Frameless Backpack State of the Market Report (reported in Part 2A), and was amazed to see the final outcome - 4090 cubic inches (67 L) for size Large, which is 890 cubic inches (14.6 L) over the manufacturer specification. The total volume includes all of the pockets and the extension collar, as is customary for frameless backpacks. For comparison, that’s about the same volume as the GoLite Pinnacle and Six Moon Designs Starlite, which are clearly in the lightweight backpack category. The lightbulb moment here is that the Aquilo is a larger volume backpack appropriate for lightweight backpacking, not ultralight backpacking.

The manufacturer is addressing the issues I mentioned and has added the following: an extra compression strap to each side of the pack (six total), two tall side pockets (for a total of four side pockets) so a hydration reservoir can be carried on the outside of the pack, an internal sleeping pad sleeve, removable internal stash pocket so it can be used as a wallet, one compression strap on top of the pack, and a Velcro attachment for hipbelt pockets. These changes correct all of the issues I raised and really zero in on creating the “perfect” pack for lightweight backpacking.

In my load carrying capacity tests, reported in Part 2B of our Frameless Backpack State of the Market Report, the Aquilo came out on top. With its stay inserted, it supported a 30-pound (13.6-kg) load with minimal pack torso collapse. The reason for this is the Aquilo’s stay actually connects to the back of the hipbelt, which is a first. Other larger volume frameless backpacks have removable stays available that slide into sleeves on the inside of the backpanel, but they do not anchor to the hipbelt to directly transfer weight. Rather, they simply stiffen the pack and assist with weight transfer via a “virtual frame.” Although the Aquilo’s stay connects to the hipbelt, it still does not create a true internal frame backpack with a built-in frame.

Elemental Horizons Aquilo Backpack Review - 6
One issue with the Aquilo is its side pockets extend to the bottom of the pack, where the mesh bottom (for drainage) is exposed to abrasion. The bottom of the pack is made of durable 420 denier urethane coated diamond ripstop nylon. Note the center pull hipbelt tightening system and optional zippered hipbelt pockets.


Comparative specifications can be found in my Frameless Backpack State of the Market Report 2011 Part 4 (coming soon). The closest comparison is the Six Moon Designs Starlite, which is slightly lighter, has slightly more volume, and costs the same.


As noted, I had difficulties using the Aquilo for ultralight backpacking. However, once I measured its true volume and moved it into the lightweight frameless packs category, it became a standout in that category.

I tested a pre-production version of the Aquilo, and provided feedback that has been incorporated into the production version of the pack. I have not seen the production pack as of this writing, but photos supplied by the manufacturer show that all of my issues have been corrected. The production version will retain its large volume, and add many significant improvements with minimal effect on pack weight. Pack weight without the stay will be 31.5 ounces (893 g) for size Medium and 33 ounces (936 g) for size Large. With the mentioned improvements, the production pack will be very competitive with the Six Moon Designs Starlite and other frameless packs for lightweight backpacking.

The Aquilo weighs about two pounds, which sounds heavy, but its weight is modest when you consider the pack’s suspension system and features. For lightweight backpacking, the Aquilo is an excellent choice for comfortably carrying loads up to about 30 pounds (13.6 kg), providing plenty of room for a larger volume gear kit, and compressing down when needed. In Part 2B of my SOTMR I compared the load carrying capacity of packs with removable stays with a lightweight internal frame backpack (the Osprey Exos 58), and found the Aquilo matched the performance of the Exos. And the Aquilo weighs about 10 ounces (283 g) less.

Overall, if you are looking for a great performing lightweight pack for lightweight backpacking (base weight under 20 pounds/9.1 kg, total weight under 30 pounds/13.6 kg), the Aquilo is definitely worth a closer look. For a new pack introduction, it looks like the Aquilo nails it.

What’s Good
  • Excellent volume reduction system
  • Durable fabrics
  • Excellent removable stay system, the best currently available
  • Excellent suspension system for a frameless backpack
  • Comfortably carries moderate to heavy loads
  • Large fabric front pocket and side pockets for convenient access to items needed on the trail
  • Excellent construction, very sturdily built, with adequate reinforcements
  • Fits well (if you choose the correct size)
  • Hipbelt pockets available
What’s Not So Good
  • Volume is way over original specification (corrected)
  • Top straps easily slip with smaller loads (corrected in revised model)
  • Bottom of side pockets extend to the ground and are subject to abrasion
Recommendations For Improvement
  • Accurately state pack volume (done in manufacturer’s new website)
  • Offer a smaller volume version of this pack for ultralight backpacking (under development)


"Elemental Horizons Aquilo Backpack Review," by Will Rietveld. (ISSN 1537-0364)., 2011-07-05 00:00:00-06.


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Elemental Horizons Aquilo Backpack Review
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Addie Bedford
(addiebedford) - MLife

Locale: Montana
Elemental Horizons Aquilo Backpack Review on 07/05/2011 18:33:05 MDT Print View

Companion forum thread to:

Elemental Horizons Aquilo Backpack Review

Warren Greer
(WarrenGreer) - F

Locale: SoCal
Neato on 07/05/2011 21:42:32 MDT Print View

I'll reread this one again. The packs not really all that heavy for what you get.

Will, didn't know that you worked for the Park Service. Good way to get out more!

Michael Davis
(mad777) - F

Locale: South Florida
Re: Elemental Horizons Aquilo Backpack Review on 07/06/2011 18:03:18 MDT Print View

This was the pack that I thought looked like a standout in the State of the Market Report! I'm glad to see that the excellent statistics become a great pack in reality. Also, I'm impressed with that fact that the manufacturer accepts constructive criticism and has been quick to make improvements. That gives me an indication of good customer service, which is why I love to deal with the "cottage industry." I think I need to start saving my pennies in the piggy bank :)

Brian Barnes
(brianjbarnes) - M

Locale: Midwest
RE: Neato on 07/07/2011 14:32:53 MDT Print View

Will does, and has done a lot... we are lucky to have him here at BPL