Outdoor Vitals CS40 Ultra Backpack Deep Dive

The Outdoor Vitals CS40 Ultra Backpack is the latest pack offering from Cedar City’s premiere ultralight backpacking company. The CS40 is a lean, mean hiking machine of a pack. Outdoor Vitals put a lot of thought into this product, and that’s undeniably clear.

The CS40 contains just the right amount of features, no excess. That’s on purpose. You won’t find any unnecessary pockets or zippers for — say, for storing your packable chessboard. However, it’s strong and stable enough to make carrying the weight comfortable.

outdoor vitals cs40 backpack on a hike

Meet the Outdoor Vitals CS40 Ultra Backpack.

There are a plethora of ultralight backpacks out there, but the Outdoor Vitals CS40 Ultra stands apart from the pack. The CS stands for carbon stay, which is the strong and super light 2-ounce frame. The 40, well, it’s a 40-liter pack, so there you go. And Ultra references the tough yet lightweight UltraWeave fabric. Considering an ultralight backpack? Then click the button below to visit the C240 Ultra’s product page, and keep reading to learn more.

See the Outdoor Vitals CS40 Ultra Backpack

Outdoor Vitals CS40 Ultra Backpack Specifications

Feature Type Feature Specs What This Means
Weight 27 ounces for the medium size Exceptionally lightweight, especially for an internal frame backpack.
Type Internal frame backpack Higher load capacity than frameless backpacks and comfortable carrying for long miles.
Material 200D UltraWeave High abrasion resistance.
Waterproof Fabric is inherently waterproof though not seam sealed Fantastic weather protection with or without a pack liner. Seam sealing is possible.
Pockets 5 Large front mesh pocket, 2 water bottle pockets, and 2 hip belt pockets. You can get a 6th shoulder strap pocket.
Capacity 53 liters 41L main body, 6L front mesh, 2L each bottle pocket, 1L each hip pocket.
Hydration Compatible This pack can be used with most water bladders.
Attachments Ice axe/trekking pole, long compression strap. Attach all you need for your expedition or thru-hike.
Weight Capacity Up to 35 pounds recommended Generous load-carrying capacity for all-day comfort.
Sizing Hip belt and torso options Choose from small, medium, and large for both the interchangeable hip belt and torso length.
Manufacturer Warranty Outdoor Vitals Performance Promise See Warranty Page
Retail Price $368 Get $50 OFF ($80 OFF for subscribers) through May 22, 2023.

See the Outdoor Vitals CS40 Ultra Backpack

Unique Features of Outdoor Vitals CS40 Ultra

Let’s start with the feature that gives the pack its name. The carbon stays are a simple 2-ounce feature that provides a lot of functionality. These stays work in place of a more traditional frame, but they do an incredible job of weight distribution.

These carbon stays are curved and contoured, cutting down on weight even further. Two ounces — that’s the difference between being comfortable and not. Adding these supporting stays will make the miles fly by far more comfortably than a frameless pack.

The ultralight industry is steering towards frameless packs, but if you have used one, you know the shortcomings. Carrying anything over 25 pounds in a frameless pack can be painful, and anything too rigid can poke you in the pack. Outdoor Vitals has created a pack as light as a frameless pack but with one.

UltraWeave Fabric

The Outdoor Vitals CS40 comes in at just 27 ounces for the medium frame with a medium hip belt, the latter being interchangeable. It’s not just the weight that is impressive about this pack. Outdoor Vitals uses an UltraWeave fabric — a 200d laminated fabric that weighs the same as 100d fabric but is vastly more durable (because it’s about 60% UHMWPE), with a virtually impenetrable waterproof rating (because it’s laminated with RUV film).

The UltraWeave fabric is unique. It’s made of 60% Dyneema fibers but utilizes other yarns to create a more supple, more abrasion-resistant, and even lighter-weight material. It has 2 times the tear strength and 6 times the abrasion resistance of traditional Dyneema fibers. It’s a more pleasing texture to touch as well.

outdoor vitals cs40 main pack fabric

The UltraWeave fabric feels great and performs well.

How the Outdoor Vitals CS40 Ultra Compares to Other Lightweight Backpacks

Here’s how the Outdoor Vitals CS40 Ultra Backpack stands up against its biggest competition.

Hyperlite Southwest 2400 vs. Outdoor Vitals CS40 Ultra

The Outdoor Vitals CS40 comes in a whole 5 ounces lighter than the Hyperlite Southwest 2400, which is impressive given how incredibly light the Hyperlite backpack already is.

One of the major differences between these two packs is how breathable they are. You’ll find closed-cell foam padding along the back and shoulder straps on the Hyperlite pack. It gets the job done, but it does get clammy and hot after some time. The Outdoor Vitals CS40 uses an open mesh and foam throughout the shoulder straps and back panel and has an airy pattern that promotes airflow.

Gossamer Gear G4-20 vs. Outdoor Vitals CS40 Ultra

The Gossamer Gear G4-20 is no slouch when it comes to ultralight backpacking. It, too, has everything you need and nothing you don’t. It is built from a mix of robic nylons, offering a solid performance-to-weight ratio. However, the Outdoor Vitals CS40 utilizes the 200d UltraWeave fabric, which is far more abrasion resistant than robic nylon, and it is also inherently waterproof, which is doubly fantastic.

In any case, you’d want to use a pack liner with both backpacks, but the Outdoor Vitals pack will give your gear more protection from the elements. Also, the Gossamer Gear doesn’t provide anything like the carbon stays in the CS40, and so you will find the load-carrying ability of the CS40 much greater than that of the GF-20. The CS40 is also rated for a minimum of five pounds more carrying capacity than the G4-20.

Black Diamond Speed 40 vs. Outdoor Vitals CS40 Ultra

The Black Diamond Speed 40 is a versatile internal frame backpack built for adventure. Coming in at 2.3 pounds for the small/medium size and 2.7 pounds for the medium/large version, this pack says much about what the wider outdoor industry views as ultralight.

The Speed 40 is extremely capable no matter if your mission calls for rock, snow, ice, or other terrains, but it’s seriously heavy. At almost a pound heavier than the Outdoor Vitals CS40, it offers similar performance and a more modular approach. Considering the weight, the Black Diamond Speed 40 may not be a good fit for an ultralight backpacker.

See the Outdoor Vitals CS40 Ultra Backpack

outdoor vitals cs40 back panel can breathe

Fully loaded and ready for anything.

Who is Outdoor Vitals?

Outdoor Vitals wants you to Live Ultralight. The Utah company creates some of the best ultralight equipment out there, and their range spans from tents to sleeping bags and even Merino shirts! They’re an accessible company that stands behind their products. If you ever have any issues, they’ll do everything they can to make it right.

the cs40 from outdoor vitals

Doing my best to Live Ultralight!

See the Outdoor Vitals CS40 Ultra Backpack, and learn more about Outdoor Vitals.

Outdoor Vitals sponsors this post.

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Jon Rosenberg

Hi, I’m Jon Rosenberg! I’m a mountain runner, entrepreneur, mountain lover, and enthusiast for just about all things outdoors. I’m based in beautiful Pagosa Springs, Colorado at the foot of the incredibly rugged San Juan Mountains. You can find me running single-track trails above treeline or backpacking the Colorado Trail. Gear is my thing. I even own my own gear company!

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