Sierra Designs 40-60L Flex Capacitor Backpack
As Low As $183.96 Save Up to 20%
View Product
Compare (0)
Featured Reviews
Most Helpful Positive Review Great backpack!
I have not been a fan of top loading packs and purchased this pack because of its weight and my experience with other Sierra Design products. I took this pack out for its first trip on the Timberline Trail in late October. We had early snow at some of the lower levels and I was happy to have a lighter pack than I usually carry and pleased with my contents staying dry. I also found the pack to more comfortable than I expected. The only drawback I had with it, was lack of attachment strapping or hoops. Something can be remedied by adding later. Did use the compression straps on the front to hold...
Read More...
All Reviews
Show
Sort by
Filter by

New backpack preview

by ser, Verified Owner from DE, United States Written on September 10, 2025
The suspension system works well and feels comfortable with all my gear. Pockets everywhere allowing gear to be organized. The stretch mesh back pockets are good for dry clothes or putting snacks.
Would recommend: Yes
Was it helpful to you? Yes | No

Sierra Designs 40-60

by Andrii, from DE, United States Written on February 26, 2025
I bought this pack for winter backpacking qnd I have only used it once for a long day hike. I had everything packed for an overnight in the White Mountains of New Hampshire in October where it was expected to be qbout 35 F overnight. The total weight of the pack was 32 pounds and it felt very comfortable when I set it up. My partner couldn't make it, so I removed some of the overnight items so that I could just do an 11 1/2 mile hike. The bag now weighed about 24 pounds. I really like how the straps on the outside of thw bag can compress it down to secure the load. The bag sits really well on your hips and the shoulder straps adjust so you can cinch the bag close to your back. I also plan to use this bag for alpine ice climbing this winter.
Would recommend: Yes
Was it helpful to you? Yes | No

Great Product! Seller was very helpful

by ser, from DE, United States Written on February 26, 2025
Love the product! I also wants to give props to the seller. I had some questions relating to my order and they got back to me very quickly and were extremely helpful!
Would recommend: Yes
Was it helpful to you? Yes | No

Flex Capacitor

by rob, Verified Owner from CA, United States Written on May 10, 2022
I really liked this pack, but unfortunately it did not fit me well so I had to return it. It is a good looking pack and it seem very well constructed. Most importantly I like the fact that the bear canister easily fit sideways in the top. I also like the pockets on the shoulder straps. The only thing I did not like was that the pack at the bottom of the pack seemed to rub uncomfortably on my back.
Would recommend: Yes
Was it helpful to you? Yes | No

light weight but with good suspension system

by Gary, Verified Owner from OR, United States Written on December 1, 2020
This is a really simple backpack, very light weight less than 3lbs. similar weight lever as HMG southwest, but the flex capacitor have much more better suspension system, even it is simple. the load transform is nice. no front mesh pocket, side pocket is not very easy to access to water bottles.
Pros:
  • light weight but with good suspension system
Cons:
  • simple
  • no front mesh pocket, side pocket is not very easy to access to water bottles.
Best Used for:
  • HIKING
Would recommend: Yes
Was it helpful to you? Yes | No

Lightweight high-quality backpack

by Wells, from Zhongzheng Dist, Taiwan Written on April 24, 2020
If you are looking for a lightweight heavy backpack, Flex Capacitor is very worth considering. The comfortable load can be up to 15kg, there is no bragging at all, the waist bags on both sides are very practical, if you remove the built-in water bag, you can reduce it 100g, highly recommend this product
Would recommend: Yes
Was it helpful to you? Yes | No

Well designed, Well made

by Uncle Eddie, from AR, United States Written on January 7, 2019
I only have a few miles on this pack but I can tell that it can handle it all. I loaded it heavy for a two night camp with my grandson and it was very comfortable. We didn’t go very far but I felt that I could have gone all day! I liked that I could expand it and then clench the load up tight.
Pros:
  • Expandable
Cons:
  • None
Would recommend: Yes
1 of 1 found the following review helpful.
Was it helpful to you? Yes | No
There are no reviews that match your criteria. Would you like to review this product?