Outdoor Vitals CS40 Ultra Review: A Lightweight Framed Pack With a Clear Weight Ceiling

Introduction

The Outdoor Vitals CS40 Ultra is a lightweight framed backpack built for hikers who want a functional, feature-complete pack without unnecessary complexity. It weighs 27 oz and lists at $368, which places it in premium territory for its class. The design pairs a 40 L internal volume with external pockets that bring usable capacity closer to 50 L, and it is rated to carry up to 35 lbs of gear.

The interesting part is where that rating actually lands in practice. This pack performs very well up to 30 lbs, and understanding that ceiling is the single most important thing to know before buying.

Who the Outdoor Vitals CS40 Ultra Is For

This pack suits backpackers who count ounces but still want a frame, load lifters, and real pocket access. It is aimed at hikers with dialed-in gear systems, since the body packs tight and compact with very little dead space, which in turn keeps the load balanced and comfortable on the trail.

It is also a good match for anyone who wants a minimal pack that still handles tall items. Side compression straps secure tent poles, a tripod, or Z-style folding trekking poles, and there is a dedicated place to stow trekking poles when they are not in use.

It is less suited to trips where the load climbs well past 30 lbs. Anyone planning long water carries or extended food carries should weigh that against the pack’s practical sweet spot.

Main Strengths

The CS40 Ultra is smartly put together. It includes the features that matter on the trail and leaves out the extras that complicate a design without adding value.

Build, Materials, and Capacity

The body uses Ultra Weave 200, a premium laminated woven fabric. Woven ultra fibers are bonded to an inner plastic film that adds structure along with water resistance. That construction proved durable in rough conditions, including heavy bushwhacking where the pack caught on branches and rubbed against rocks.

Capacity is 40 L internally, with two side pockets and a front stretch mesh pocket pushing usable space to around 50 L. The roll-top closure keeps the profile tidy and lets you compress the pack as the load shrinks.

Carry Comfort and Frame

The back panel is built for long days under load. Contoured shoulder straps use dense foam that supports weight without creating friction or pressure points, and cutouts in the straps add breathability. Load lifters attach at the top of the frame, which is formed by carbon fiber stays that resist collapsing under weight.

A large U-shaped foam panel sits against the back for comfort and airflow, while the lumbar area is rolled to follow the natural curve of the lower back. The hip belt pockets are a highlight: easy to open one-handed and simple to adjust. Comfort is solid up to 30 lbs.

Pocket Design and Access

The two side pockets are generously sized and hold two large water bottles each, or bulkier items like a camping chair. More importantly, bottles go in and come out easily while the pack is worn, with no need to take it off. That kind of access matters on every hike.

The strap over the roll top fits a chair, a jacket, or a closed-cell foam pad. It is not long enough to secure a bare bear canister.

Things to Consider Before Buying

A few details are worth weighing before you order, and most of them come down to how hard you plan to push the load.

The front stretch mesh pocket is very stretchy and useful for drying wet gear, but it is the least durable part of the pack. It snagged a hole during bushwhacking and will likely wear further with that kind of use. A tougher stretch material would suit the pack better, even at a slightly higher price.

The side pockets are close to ideal, but a little more volume and a slightly taller front pocket would make double-bottle carries less tight and give more confidence that items stay put.

Hip Belt Under Heavier Loads

The hip belt is comfortable up to 30 lbs, but its limits show under more weight. During a water carry near 35 lbs, the bottom of the hip belt collapsed noticeably where the foam ends, since it connects by a piece of velcro and is not very rigid there. At around 36 lbs the result was hip bruising.

The same velcro attachment point also caused loud squeaking as fabric rubbed against fabric with every step. The webbing on the hip belt is short, so ordering the correct belt size matters.

Small Details That Could Improve

A few refinements would improve the experience. The sternum strap has no stretch, so a snug fit can restrict breathing during deep breaths. The roll top could use more rigidity for a tighter, more secure roll. And the shoulder straps lack accessory loops, which limits options for third-party add-ons such as a satellite device pouch or a capture clip.

Buying Advice

Buy the CS40 Ultra if your typical load sits at or below 30 lbs and you value a light, functional framed pack. It carries that weight exceptionally well, and the carbon fiber frame, load lifters, and pocket layout all earn their place.

The pack comes in three torso sizes and three hip belt sizes, so match both to your body rather than defaulting to a middle option. If your trips regularly push past 30 lbs, plan for a different pack or accept a real drop in comfort.

Also worth noting: the fabric resists water, but the pack is not fully waterproof. Seams can leak over time, so use a pack liner in consistently wet conditions.

Conclusion

The Outdoor Vitals CS40 Ultra is a well-executed ultralight framed backpack at 27 oz and $368. It is durable where it counts, carries 30 lbs with genuine comfort, and keeps water bottles and essentials within easy reach.

Its weak points are specific: a fragile front mesh pocket, a hip belt that gives up past 30 lbs, and a handful of small refinements that would make it even better. Buy it for the weight range it was designed around, and it is a strong choice.