Arc Haul Ultra 70L Backpack

6 reviews
$399.00 Weight 21.9 oz / 621.0 g

Lead Time Ships in 1-3 Days

Long days between resupplies requires a pack designed with ample space and durability. Made from "Ultra 200" material, the ultralight Arc Haul Ultra backpack is innovatively designed to be a true workhorse from the Sierras to the Shenandoah.

Comfortably transfer your pack’s weight to your hips with our custom Curved Carbon Fiber frame system. The frame also creates a gap between your back and the pack allowing for air flow that helps keeps you cool.

Featuring adjustable shoulder straps, an interchangeable belt, and a variety of optional modular add-ons, the Arc Haul Ultra will allow you to tackle those long days on the trail with a durable ultralight backpack designed to fit you.




  • Made from Black Ultra 200 fabric with an optional weight-saving accent color in gray Ultra 100 fabric. Ultra fabric features a woven Ultra High Molecular Weight Polyethylene (UHMWPE) face fabric laminated to a waterproof backing. Ultra fabric boasts extremely high abrasion and tear resistance and is the strongest fabric we offer.

  • Curved Carbon Fiber Air Stays combined with a Lycra back panel create a gap between your back and the pack. The air gap helps keep your back cool while also preventing items from rubbing against you while hiking.

  • Roll-top closure (like our dry bags) keeps water out, and lets you roll down the top as your gear load shrinks. All seams and attachment points are taped, making the pack highly water resistant. We still suggest using dry bags for your important items like your sleeping bag.

  • Comfy 3/8" thick by 2.75" 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 up to two 1L hard bottles, or 2L soft bladders. 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.

  • Large stretchy 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.

  • Side compression straps are made from non-stretchy Dyneema® cord for squishing down the pack volume. They also allow you to stand tall items like trekking poles or an umbrella in the side pockets.

  • 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 70L pack size has enough space for 7-10 days of food and ultralight gear. The pack can be compressed down with the roll top and side compression straps for short trips or use the top strap and base straps to lash extra stuff to the outside for long carries.

  • Some full size Bear Canisters, including the BearVault 500 will fit horizontally in the 70L pack size. Our smaller packs require the canister to stand vertically. Wrap your canister with your sit pad, or clothing to help prevent abrasion to the inside of the pack material.

  • 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.

  • 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 and Lycra back panel 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 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 here.

  • 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 40 lbs (18 kg).

Load Capacity: 40 lbs (18kg)

Body dimensions: 9.5" x 12.5" x 29" (24.1 cm x 31.8 cm x 74 cm)

Volume: 70L (57L main body, 2.5L each side pocket, 8L center pocket)

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

2.92oz/sqyd Ultra 100

Ultra 100 is composed of a woven 100 denier Ultra High Molecular Weight Polyethylene (UHMWPE) face fabric laminated to a waterproof lining. It is inherently waterproof and has extremely high tear and abrasion resistance.

Our Repair Tape and Adhesive products stick extremely well to the interior of this fabric.

Tear Strength: 69.4 lbs. warp; 89.6 lbs. fill

Water Resistance:
 >20,000 mmH₂O

3.5 oz/sqyd Ultra 200

Ultra 200 is composed of a woven 200 denier Ultra High Molecular Weight Polyethylene (UHMWPE) face fabric laminated to a waterproof lining. It is inherently waterproof and has extremely high tear and abrasion resistance. This is the strongest fabric we carry.

Our Repair Tape and Adhesive products stick extremely well to the interior of this fabric.

Tear Strength:
 103 lbs. warp; 133 lbs. fill

Water Resistance:
 >20,000 mmH₂O

.3.5 oz/sqyd Mesh

This is the mesh that we use on our backpack's center 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. The hole size is a about 4 mm (a little over 1/8"). 

 3.5 oz/sqyd (119 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 (30-36 inches)" belt has padding which measures about 29" tip to tip, and has a minimum adjustment circumference of 30". It is the recommended size if your actual measurement is up to 36" however the webbing extends further.

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
3.8 Based on 6 Reviews
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Michelle B.
United States United States

Great light efficient backpack!

I love this pack Very comfortable, super light and very well thought!

Zpacks Arc Haul Ultra 70L Backpack Review
Mark M.
United States United States

Good pack

Bought this pack for a PCT section hike. Light weight, fit well, materials and stitching very good. Carries like a frame pack without the weight. Mesh panels stronger than I anticipated. Shoulder straps somewhat comfortable, I'll be purchasing the extra shoulder pads. Same with the waist belt, could be improved with the additional lumbar pad. One negative: the middle horizontal stay tends to pop out of the nylon pockets when loading the pack. Annoying but not a fatal error. One suggestion for the Zpacks: include the Y strap for the top closure in the standard model. The single straps works but the Y strap holds better. Of course, that may be my own personal esthetic. Love the fact that this pack is Made in the USA.

United States United States

Great for longer trips

I have walked just over 100 miles with this pack containing about 40 pounds, no issues with the pack at all. Airflow on my back has been fantastic, and comfort has been about as high as possible without wearing a pack that weighs ~7 pounds. I use the lumbar and shoulder pad accessories, these may be the things that help with the extra weight that the other reviews may not have had. Highly recommend the belt pockets, they are enormous (so many snacks!). If you find the airflow lacking, the back panel can be tightened. The stiffer straps ensure a gap between your back and the panel. Even with the panel tight, if you pack poorly the bag can be touching your back. Anything flat (or just not-super-round) can be placed in the bag along your back to prevent the bag from touching the back panel, thus touching your back.

United States United States

Not Great for Carrying Weight

Right out of the box I was excited by how light and durable this bag felt. After filling most of the 70-liter space and trying it out on shorter hikes around my place, I quickly realized this bag would not work for a through-hike. I needed to cinch the waist straps down pretty tight in order to keep the weight off my shoulders which was really uncomfortable on my stomach over time. Even then, the majority of the weight rested at the base of my back, rubbed against and dug into it while I moved. Given the issues I experienced, I don't get why Zpacks offers an ultra-light bag at this size. It's pretty uncomfortable at a pack weight of around 30lb which was unexpected for the volume it's able to hold (I followed the measuring guide and even called for more clarification before purchasing).  The final nail in the coffin was trying to return this item. Zpacks didn't accept it and pointed to their return policy which (fair enough I guess) states that you basically can't take the bag out of your house after it arrives. Not sure how you're supposed to get a good feel for a bag you're planning on taking out for multiple weeks by doing laps in your living room. Bottom line: For a $400 purchase, I expected more from the product and from Zpacks customer service. 

Christopher T.
United States United States


LOVE my Arc Haul 70L. The previous reviewer mentioned that the pack is uncomfortable when fully loaded, but I completely disagree! My previous pack was a Gregory Baltoro 75L, and I find the Arc Haul to be much more comfy. My only complaint is that additions to the pack, such as hip belts and lumbar support options, are a la carte. I guess one pro of this is that you can customize the pack to your specific needs, but at a premium price. As a thru hiker I can’t wait to use this on long hauls!