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ZPacksô Arc Blast Backpack


Our Patent Pending Flexed Arc carbon fiber frame creates an air gap against your back for a super comfortable fit. The air space keeps your back cool and also provides a buffer from any lumpy items in your pack. The curve of the frame is adjustable for optimal air flow and fit. No extra padding necessary.

The pack is constructed from tough 2.92 oz/sqyd Cuben Hybrid fabric. This material is Cuben Fiber on the inside with a protective layer of 50 denier Polyester on the outside. The outer layer gives it even more strength, prevents fraying, and gives it a nice solid color. The material and design can handle loads up to 30 lbs (14 kg).


There are three pack volumes to choose from. The torso height and belt size choices are independent of the pack volume.

45L Pack Size:
Total Volume: 45 Liters / 2,750 cubic inches - 16.8 ounces (476 grams)
Main Body Volume: About 32 Liters / 2,000 cubic inches
Body dimensions: 5.5" x 12.5" x 30"  (14 cm x 31.8 cm x 76 cm)

52L Pack Size (the original default size):

Total Volume: 52 Liters / 3,200 cubic inches - 17.0 ounces (482 grams)
Main Body Volume: About 39 Liters / 2,400 cubic inches
Body dimensions: 6.5" x 12.5" x 30"  (16.5 cm x 31.8 cm x 76 cm)

60L Pack Size:
Total Volume: 60 Liters / 3,650 cubic inches - 17.2 ounces (488 grams)
Main Body Volume: About 47 Liters / 2,850 cubic inches
Body dimensions: 7.5" x 12.5" x 30"  (19 cm x 31.8 cm x 76 cm)

The side pockets account for 5 Liters / 300 cubic inches and the mesh center pocket is 8 Liters / 500 cubic inches, and are included in the total volume.

Standard Features on the Arc Blast backpack:

Torso Height:

The torso height on our backpacks is the actual distance on the backpack measured from the bottom of the belt to where the shoulder straps attach. Your best bet for sizing is to find an existing pack that you like and measure it directly. Note that the curve of the Arc frame affects the position of the shoulder straps, and the curve is factored into our measurements. The shoulder straps should be positioned level with, or a bit below the tops of your shoulders.

By default this backpack comes without Load Lifter straps, and they aren't really necessary for ultralight loads. If you do add Load Lifters it is ok to have the shoulder straps a little lower, because the load lifters pull the straps up off your shoulders.

If you aren't sure about the torso height, or if you want more flexibility there is also an option below to add an adjustable torso range.

Belt Size:

The belt size is the length of the belt padding from tip to tip. For example, a medium 30 inch (76 cm) belt has 30 inches of padding from tip to tip. The belt can cinch down to the point of the padding just about touching in front. The belt webbing extends at least 10 inches (25 cm) or more beyond the padding.

Use a string or cloth tape measure pulled tight around the spot on your body that you want the belt to ride. You want at least a few inches of webbing in front to allow for adjusting the buckle. If you are on the line, size down so that you have room for adjustment. As an example, if you measure 35 inches, a medium 30 inch belt would give you 5 inches of webbing to adjust in front but a large 34 inch belt would barely fit with almost no room for adjustment.


Note that the "Indigo" color looks blue in the photos but it is actually a deep blue-purple. Indigo and Orange backpacks have a Gray panel against your back as shown. All the other color choices are a solid pack color. All packs have black pockets.


Backpacks are made to order. There is currently a lead time of about 5-6 weeks. We are unable to take additional due date requests until our backlog is shorter.

Please note that if you choose a torso height of 23" or up, the backpack frame is lengthened from 22.75" (58 cm) to 25.25" (64 cm).

Arc Blast Backpack - $295
Torso Height
Belt Length

Additional Options:

Adjustable Torso Height and Load Lifter Straps

This feature is borrowed from our Arc Haul backpack. It allows you to move the shoulder straps up or down within a range to dial in a perfect fit. It works like a conveyor belt. This is useful for young hikers who are still growing, or if the pack may be shared among people with varying heights, or for resale value down the road.

This option Includes Load Lifter straps, so don't add them separately below. Load lifters help lift the straps up off your shoulders, and they pull the top of the pack in closer to your back. You can position the shoulder straps just below the top of your shoulders.

This option overrides whatever torso height you selected above. Please note that if you choose the Tall torso height range, the backpack frame is lengthened from 22.75" (58 cm) to 25.25" (64 cm). If you are on the line and do not want the taller frame sticking up behind your shoulders, get the Medium torso range.

Weight: 1.0 oz  /  28 grams each   Price: $15

Torso Height:

Load Lifter Straps

If you prefer to keep your shoulder straps attached to the backpack at a fixed position, you can add Load Lifter straps by themselves. They connect the shoulder straps to the top of the frame. These can be helpful to pull the shoulder straps up, and pull the top of the pack in towards your shoulders. These aren't strictly needed for ultralight loads.

Weight: .2 oz / 5.7 grams Price: $8

Shoulder Pouches

These clip to your shoulder straps and are an excellent spot for your camera, GPS, phone, sunglasses, or other items that you want to grab quickly. Mesh on the front of the pouch gives you additional storage for small items like chap stick, keys, etc. They can also be used for .5L water bottles to counter balance a small pack.

These are detachable and can be used on non-ZPacks backpacks as well. They are symmetrical and can be switched left or right.

Weight: .5 oz  /  14 grams each   Price: $21.95 each / $41.95 pair

Shoulder Pouch Details Here

Belt Pouches

These pouches clip securely to the daisy chain on your padded belt. They have taped seams, a waterproof zipper, and are highly water resistant. Each pouch has about 1 liter of volume and is perfect for maps, snacks, hat and gloves, gadgets, you name it.

These are detachable and can be used on non-ZPacks backpacks as well. They are symmetrical and can be switched left or right.

Dimensions: About 6" wide, by 2" deep, by 5" tall.

Weight: .75 oz / 21 grams each  Price: $21.95 each / $41.95 per pair

Belt Pouch Details Here

Multi-Pack - Four in One Backpack Lid / Chest Pack / Belt Pack

This four-in-one backpack accessory can be attached to the top of your pack as a lid, carried on your chest as a front pack, or worn at your hips as a fanny pack, or carried over your shoulder as a satchel.  About 3.5 liters / 215 cubic inches volume. This will also work on non-ZPacks backpacks as long as there are loops to clip it to.

2.9 ounces - 82 grams   Price: $39.95

Multi-Pack Details Here

Top Side Pockets

These pockets have a loop at each corner to connect them to corresponding loops on the sides of your pack. Since these are not sewn to the pack you can still stand tall items like trekking poles, an umbrella, or a fishing pole behind the pockets. The pockets can be taken off or added later.

The dimensions are roughly 6" wide x 3" deep x 8" tall. They are a good fit for:
-A 1 Liter or smaller pot
-A 1 Liter water bottle
-A water filter
-A poncho or light jacket
-Hat and gloves
-An inflatable sleeping pad.

Weight: .5 oz / 14 grams each Price: $18 each / $35 per pair


Key Pocket

A small pocket with a zipper is sewn inside the backpack just above the shoulder straps. This is a good spot to safely store your car keys and wallet until you get back to the trailhead. The pocket is located near the top of the pack so that you can access it w/o digging too far into your gear.

The pocket measures about 7" wide x 5.5" tall (18 x 14 cm).

Weight: .2 oz  /  6 grams    Price: $10

Ice Axe Loops

A pair of loops are attached at each corner of the pack for securing ice axes, one at each corner. The head of each axe secures through a loop at the bottom, the handle is kept tight at the top with a shock cord band. The loops can all come off when you aren't carrying axes.

Weight: .1 oz  /  3 grams    Price: $3

Trekking Pole Holders

One adjustable shock cord loop is attached to your shoulder strap and another loop is attached to your belt to temporarily hold a trekking pole. These are convenient if you want to quickly stow your poles for climbing, or road walking, or other situations where you don't need your poles temporarily. You can stow them and retrieve them without stopping to remove your pack. You can carry both poles on the same side if you prefer.

You can easily attach these to any older ZPacks backpacks, or other brand packs. They can be moved to either side, or you can get them on both sides.

Weight: .2 oz  /  6 grams per side    Price: $3 per side


Shock Cord Lashing

3/32" Shock cord is criss-crossed along the front of the backpack. It can be used to compress the pack, or to strap on items. The shock cord can be detached when not needed. It does get in the way of the center pocket a bit.

Weight: .5 oz  /  14 grams    Price: $6

Lumbar Pad

A lumbar pad cushions your lower back and increases the air gap behind your back slightly. If your belt is just a little too large, this reduces the belt circumference by about an inch. Typically you might carry something soft at the bottom of your pack like your sleeping bag, so you may not need any extra padding at the lumbar area.

This pad slides on or off your existing belt and is held in place by two bands on the back. It is also tied in place at the bottom center so that it can't ride up or down. This may not fit on non-ZPacks backpacks.

Weight: .6 oz  /  17 grams    Price: $12

Roll Top Dry Bags

Up to 6 size medium or medium-plus size roll top bags will fit inside the body of the pack, and up to 3 more can be strapped on to the top and bottom of the pack for long carries. That's alot of capacity! Put your heaviest items (food, water) on the inside of the pack close to your center of gravity, and lightweight items (tent, clothes, pad) on the outside if you run out of internal space. The Large Rectangle Food Bag  is a good fit for this pack.

Roll Top Dry Bags

A medium Cuben Fiber Pack Cover, or a Pack Liner are also sized for this pack.

Custom Options

If you have emailed us about adding special features to your pack you can add custom charges to your order from the Payments page.

Back Story:

The Arc Blast backpack was originally designed in 2012. Prior to that most of our backpacks were "frameless" and relied on a folded or coiled sleeping pad for support. I did my first three thru-hikes (AT, PCT, CDT) with frameless packs very similar to our current Zero backpack. Frameless backpacks are ok for super ultralight loads, but they start to get uncomfortable on the shoulders when they are pushed beyond about 20 lbs (9 kg). On a long hike, heavier food and water loads are inevitable.

Our goal was to create a comfortable pack with a frame without adding any more weight than necessary. A frame keeps the pack rigid making it easier to pack and it also holds its shape when half full. A frame transfers weight to the belt, and feels alot better on your back and shoulders when pushing weight loads into the 20-30 lbs range.

My wife Sheryl and I gave Arc Blast backpacks their first big test on our 2012-2013 Te Araroa thru-hike in New Zealand. This hike was close to 1,900 miles and four months long across all types of terrain the length of New Zealand (Trip report / Gear list).

Our packs held up very well on that trip with minor wear and tear. Since then we have added taped seams and more strategically placed reinforcements for even better longevity. Our packs felt great. They were a big improvement in comfort over the frameless packs we had used in the past. The extra few ounces for the carbon frame was totally worth it, and the cushion and air flow against our backs was appreciated in the warm, wet, humid New Zealand weather.

Our longest carry on that trip was through the Richmond Range. We carried a starting weight of about 35 lbs (16 kg) with 9 days of food. The Arc Blast feels "heavy" at that weight, but not terribly uncomfortable. It is ok once in a while. The recommended comfort limit is about 30 lbs (14 kg). If you need to carry higher loads regularly, consider the Arc Haul backpack.

Reviews and Customer Testimonials:

Please email us with feedback (good or bad) if you have any!

"What really sets it apart in the market; itís amazing that a pack weighing so little can carry so well."
Read the Arc Blast Review at HikeitLikeit
CleverHiker Top Pick! - Read the Full Arc Blast Review at

Will Wood gives a Post-Appalachian Trail Thru-hike Video Review of his Arc Blast backpack after 7 months of use.
Adventure Writer Keith "Fozzie" Foskett reports from his 2013 El Camino de Santiago thru-hike with his Arc Blast!
Read his informative Arc Blast review with photos.

Update- Keith has finished his second El Camino de Santiago hike in 2014. "My Arc Blast now has 1900 Miles on the clock and it barely seems worn in."
"On the impressiveness scale, I would put the load carrying abilities of the ZPacks Arc Blast, for loads in the sub 20 range, at exceptional."
Check out the full Arc Bast Review by John Abela (
Matt D. reviews his Arc Blast Backpack and his Hexamid Solo-Plus tent and poncho.
2012 PCT Hiker Spider Legs reviews his first generation Arc Blast Backack.
"The Tour De Mont Blanc was amazing! The Arc Blast did exceptionally well carrying all of my gear and food for 8 days of travel through the French, Italian, and Swiss Alps!" -Ben Smith (
"I just wanted to let you know that I received the pack today. I had extremely high and unfair expectations from the reviews and recommendations I had received, which the Arc Blast has (somehow) more than surpassed! This is my first ZPacks product and I am just blown away by the craftsmanship and functionality. I was expecting some imperfections from a smaller company, but the stitching and the water taped seams are just beautifully done, as is the rest of the pack. On top of all that, I just loaded it up with a lot extra gear and the weight transfer is unbelievable, couldn't really tell the difference between 1 pound and 15 pounds." -Rocky J.
"Got back from my Sequoia adventure with the Arc Blast pack. I was a little apprehensive, I didnít think a one pound pack would handle 35 pounds, expedition canister with food for 9 days included. We weighed them with scales before heading off to trail. At that point I was committed and thought ďoh boyĒÖ. I must say this was the most comfortable pack Iíve ever used. And Iíve used ULA, Six moons, and granite gear stuff. Pleasant surprise!" -Chuck T.
"Thanks for the Arc Blast. We loved it. Best, and lightest of the breed. We used it for four days and three nights through about 32 miles and 6000ft of up and down , rain, sleet, hail, and snow without any fault or discomfort. Also, survived six airplane rides and several mad dashes through the airport with a full load. I'm sure this is nothing compared to what others have done with the pack." -Arlo A.
"I have been using the 60 liter Arc Blast backpack I purchased from you for a couple months now.  I love the pack and I think it's  the most perfect designed and constructed pack to be found anywhere.  I have shown the pack to lots of hikers and recommended it to everyone." -Chuck F.
"Your products have changed my life. I went on the most comfortable backpacking trip of my life last weekend using the Arc Blast, sleeping bag, hood, toothbrush, towels, just about everything you sell, haha. Thanks so much for the wonderful products and your amazing customer service, I will be singing your praises up and down the PCT this summer." -Otto R.
"Alyson & I canít thank you enough for how much we enjoyed the zPacks gear during our recent walk in Spain. Itís not just the light weight Ė the Arc Blast packs are so well designed we just put our gear in and everything was so easy to access when we needed it." -Mark & Alyson
"The backpack was comfortable and survived the harsh environment on the Larapinta Trail in Australia. One of the most comfortable packs I have used. Just large enough for 10 days gear and dehydrated food, three litres of water and SLR camera. Start weight about 17kg." -Peter J.
"Just completed the GR-5 last week in France. The pack was fantastic, easily carrying 10 kgs, completely water resistant through every thunder storm, and unbelievably light. Thanks for a great piece of gear." -Avi. (photo)
"I seem to have (inadvertently) got the JMT southbound record time 4 days, 8 hours, 43 minutes. I used a lot of ZPacks kit on this trip - Arc Blast pack, Hexamid tarp, ZPacks sleeping bag, WPB rain jacket and kilt." -Ralph Burgess
 I am not a super-light hiker but an older guy incrementally dropping weight. I was surprised how comfortable the Arc Blast was. I expected to "give something up" in order to drop weight. Not the case with the Arc Blast! -Doug L.
"The pack is great! 6 days in the Grand Canyon loaded with water, 8 days bushwhacking in the Wind Rivers, 6 days on the AT, all loaded for the duration. Carries far more weight than you rate it for and does so well ... it's a beautiful thing and my favorite of all my packs!" -Bob M.
"The Arc Blast I got some time ago worked great at Philmont this summer, even when hauling up to 50lbs. The Scouts still haven't learned anything about light weight food, so we had plenty of canned goods and gallons of water due to the drought. The pack was uber comfortable, even under such heavy loads. Love your gear!" -Daniel L.
Disclaimer: You probably should not carry 50lbs in this pack, but it is nice to know that you could in extreme circumstances. 30-35lbs is a more reasonable upper limit.
"I just returned from a 10-day trip in the Sawtooth Wilderness in Idaho. The Arc Blast pack was wonderful. It is the best backpack that I have ever owned. Thank you for lightening my load by approximately 2 pounds from last year's trip!" -Todd G.
"I used the Arc Blast on my recent JMT thru hike. The pack performed perfectly! It was super comfortable even with 7 days food in my 12" Bearikade (about 31 lbs total weight) and shows no visible wear and tear. I actually saw several other hikers with the same pack and 100% of the people who had them loved them! I put the Bear can in the middle of the pack to avoid any  potential wear and tear on the bottom, and the weight distribution was great." -Mick P.
"Thank you for quickly sending out my new backpack to Reds Meadows. My old pack was falling apart and I was able to complete the John Muir Trail without interruption. The Arc Blast fits perfectly and was a joy to carry. Many people asked about it and we gave them your website! The Hexamid solo is still working wonderfully after 3700 miles too! Hope you continue to have great success with your business." -Jellybean
"I just finished a JMT thru-hike with a 60L Arc Blast and a Hexamid Duplex, and they both worked fantastically. The pack held my BearVault 500 with a peak weight of about 25 lbs without problem, and it still looks in good shape!" -Austin L.
"This year I was trekking in the French Alps and found Arc Blast just fantastic! It sits very well on your body, I could easily adjust the frame to regulate the distance between the pack and my back, size and placement of the side pockets is very good, my drink bottles and small snacks were very safe there. I felt like backpack was very well 'united' with my body. We were trekking through some difficult terrain and it was very comfortable, I'm really impressed. I did get some tiny scuffs on the bottom from resting it on sharp rocks, but other than that it is great. I'm so glad my friend told me of your website." -Ewa K.
"Just wanted to send a quick thanks for my Arc Blast! I have been absolutely loving it and giving it a workout. Best pack I have ever owned. Here's a view of the Chinese Wall in The Bob Marshall Wilderness." -Will F.
"I received my 52L Arc Blast a couple of weeks ago and am more than impressed with the quality, workmanship, and the overall comfort! Iíve never hiked 20 mile days in a more comfortable pack! I donít even feel like taking it off during breaks on the trail! Its INSANE!!! I tell all my hiking partners and friends about you guys!" -Rock S.
Fellbound discusses the merits of his Arc Blast Backpack and his Challenger Rain Jacket in this Arc Blast Review.