Arc Air 50L ROBIC Backpack

3 reviews
$299.00 Weight 21.6 oz / 612.0 g

Lead Time Ships in About a Week

From those grueling east coast ascents to long water carries across the desert, the Arc Air is a durable pack designed to be the ultimate combination of simplicity and function.

Featuring custom Curved Carbon Fiber Air Stays, the Arc Air creates a gap between your back and the pack without the need for a mesh back panel.  The frame transfers weight to your hips, keeping the weight off of your shoulders and providing a comfortable fit.

The ROBIC® version of the Arc Air is highly durable and provides added abrasion resistance over the DCF version.

Featuring adjustable shoulder straps, an interchangeable belt, and a variety of optional modular add-ons, the Arc Air is sure to become your pack of choice.

  • Constructed from a mix of 3.7 oz/sqyd 100D and 5.8 oz/sqyd 210D ROBIC® Material.

  • Curved Carbon Fiber Air Stays create a gap between your back and the pack without the need for a mesh back panel. The air gap helps keep your back cool while also preventing items from rubbing against you while hiking.

  • The roll top closure keeps water out, and lets you roll down the top as your gear load shrinks. The buckles can be clipped to each other for simplicity, or they can be clipped to the side compression straps to squish down your gear load further. The side compression straps allow you to stand tall items like trekking poles or an umbrella in the side pockets, or they can be detached if not needed.

  • The pack material is waterproof and is constructed using hydrophobic thread, making the pack highly water resistant. We still suggest using dry bags for your important items like your sleeping bag.

  • Large stretchy Lycra mesh center pocket is great for quick access items. Mesh also lets you dry wet clothing and gives you a clear view of your gear.

  • Comfy 3/8" thick by 2.5" wide padded contoured shoulder straps and padded belt. Both the straps and the belt have a daisy chain for clipping on items, and an adjustable position sternum strap is also included. The belt and shoulder straps have 3D mesh on the underside. This gives them a little bit more cushion, and the belt also has more texture for better grip.

  • Side pockets are sized to fit 1 or 1.5 liter bottles. They are positioned low on the pack and slanted forward for easy access without removing the pack. The pockets have drainage holes at the bottom, and elastic that keeps them tight at the top.

  • A top strap, and base straps allow you to lash on extra items to the top or base of the pack. The straps come off if you don't need them.

  • The 50L pack size has enough space for 4-5 days of food and ultralight gear. The pack can be compressed down with the roll top closure straps for short trips or use the top strap and base straps to lash extra stuff to the outside for long carries.

  • All standard Bear Canisters, including the Bearikade Expedition and the BearVault 500 will fit in the upper half of this pack standing on end. There is enough extra girth to either wrap a foam pad around the canister (if you use one) or stand a medium stuff sack vertically beside the bear canister.

  • The short and medium size frames will fit into an airplane overhead bin with the top rolled down to the frame. The tall size frame may not fit unless you pop the vertical frame bars out of the pack.

  • The sides and front of the pack feature a variety of loops for attaching optional add-ons like our top side pockets, shock cord lashing, and ice axe loops.

  • Our torso height adjustment mechanism is is covered by US Patent No. 9,848,687

  • All Zpacks gear has a two year limited warranty against defects in materials or workmanship. Please see our return / warranty policy.

  • Made in the USA.
  • Our ultralight Curved Carbon Fiber Air Stays keeps the pack stiff so that most weight is carried on the hips instead of the shoulders. The frame pieces can be easily removed or replaced.

  • The frame is curved to allow air flow and keep your back cushioned from the pack's contents. The arch is about 2.5" (6 cm) deep.

  • The belt is attached directly to the bottom of the pack frame for the best load transfer.

  • The belt is removable and interchangeable. If you lose weight or need to share the pack between people, the belt can be swapped out. Watch the belt removal video.

  • The shoulder straps and load lifter straps are attached directly to the frame. Load lifters straps come standard on this pack.

  • The shoulder straps can move up or down to adjust the torso height to a perfect fit using our patented torso adjustment mechanism. It works like a conveyor belt. This is great for sharing the pack between people, for growing teenagers, or for resale.

  • The belt provides a full wrap around your back. No need for additional lumbar support.

  • The belt is done with "V-Style" webbing so that the top and bottom circumference can be adjusted independently. This helps wrap your hips much more securely and prevents the belt from sliding down.

  • Collectively, these features provide the additional load transfer necessary for loads up to around 35 lbs (16 kg).


Body dimensions: 6" x 12.5" x 29.25"  (15 cm x 31.8 cm x 74 cm)

Volume: 50L (37L main body, 2.5L each side pocket, 8L center pocket)

Frame Height: Short 17" (43 cm), Medium 20" (51 cm), Tall 23" (58 cm)

3.7 oz/sqyd 100D ROBIC®

ROBIC® nylon has very high tensile strength for its weight. The material features a fully waterproof polyurethane coating. The exterior is treated with a C6 durable water repellent. This material is used for the main body of the Arc Air.

Weight: 3.7 oz/sqyd (125 g/m²)

5.8 oz/sqyd 210D ROBIC®

We use this heavier weight of ROBIC® to add strength and durability in high wear areas. We use this material for the bottom, rear, and pockets of the Arc Air.

Weight: 5.8 oz/sqyd (197 g/m²)

5.0 oz/sqyd Lycra® Mesh

This mesh provides a superb 4-way stretch and is a great choice for exterior backpack pockets. It has a relatively light weight for mesh, while being difficult to tear. It can withstand getting caught on branches and other typical abrasion that backpacks are subjected to.  

 5.0 oz/sqyd (169.53 g/m²)

5.3 oz/sqyd 3D Spacer Mesh

This mesh has a three-dimensional structure which allows airflow and adds cushioning. It has a tricot backing so you can't see clear through the holes. We use it on the underside of our backpack's shoulder straps and belts to absorb sweat, add cushion, and add grip. Our 3D mesh weighs less than most other types.

 5.3 oz/sqyd (180 g/m²)

 About 3/32" (2.5 mm)

Torso Height:

To measure your torso height, you will need the help of a friend and a string or cloth tape measure.

Most hikers wear their belt near the top of their hips, however, it isn’t uncommon for hikers to position their belt higher or lower.

To ensure you lock in the perfect fit, we suggest putting a belt on over your clothes in the spot where you’d like to belt to ride. Start your measurement at the center of the belt where it meets your spine.

Lower your chin towards your chest.  This will cause the C7 vertebrae to protrude at the base of your neck. The C7 vertebrae will mark the top of your torso height measurement.

Using the string or cloth tape measure, follow the curve of your spine up from the center of your belt to your C7 vertebrae.  This measurement is your torso height.

Belt Size:

The padded portion of the belt is 1" shorter than the listed minimum adjustment. For example a "Medium (30-45 inches)" belt has padding which measures about 29" tip to tip, has a minimum adjustment circumference of 30" and a maximum adjustment of 45"

To measure your belt size, pull a string or cloth tape measure tight around the spot you’d like your belt to ride. Choose a belt with a minimum adjustment of a couple inches smaller than your actual waist measurement. This will leave room for you to tighten down the belt if you lose a little weight on trail.

The belts on our Arc Series packs are also removable and interchangeable. This will give you the ability to switch the belt out if your waist size changes or if you order the incorrect size by mistake.

Customer Reviews
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Carah B.
United States United States

My first UL

It was great, I ordered online & my backpack arrived in the time the said. I have only got to carry it on a day trip so far but it felt good & I really like it.

Loraine C.
United States United States

Arc air Robic

I liked it very much - used it for 170 miles on the Appalachian Trail. Love the color (orange!!). I only had one issue with this pack - the fixed bent frame was not sufficient enough to let air through my back. On my other Zpack I could adjust it........ is there a way that I can get more curve on the frame?

A Zpacks Customer
Canada Canada

Pack Evolution!

Firstly I’m a self-diagnosed Zpacks addict. I've tried so many other brands and I seem to always pick the Zpacks option. This pack is no exception. Fit, comfort, and utility are second to none, so let’s look at the design. The webbing on the whole length of the shoulder straps is simple but super useful for attaching all sorts of goodies, like water bottle carriers, cell phone, and camera bags, etc, etc... the mesh front pocket I believe a misunderstood asset. Much tougher than the “new” trend towards stretchy blends and also much better for airflow and drying. The Robic material I like better than DCF in my opinion for a backpack. Tougher, a tiny bit heavier, and water-resistant enough. The new “backless panel” arc design is brilliant, and so far so good - I’m less committed to this design with only 150km using her so far. Stayed tuned for a 1000 km update! I already have 1000 plus kilometers with my Nero, and 500 km with my Arc Haul. I see the Arc Air is smack dab in the middle. Almost as if NERO and HAUL had a baby it would be the ARC AIR. :) It has many features of both and some uniquely like the NERO while other features like the HAUL. Re. sizing... I have a 19.5" back and originally tried the SMALL and returned it for the MEDIUM. It's a much better fit for me. Bottom line... it's a winner, comfortable, light, tough, and well designed. I will be taking her on my summer GDT hike in 2021!