Gear Review: Gossamer Gear G4-20 Ultralight 42 Backpack

The Gossamer Gear G4-20 is a new take on one of the classic GG packs with some really cool and unique new features. Most notable are the asymmetrical hip belt pockets and side pockets that are made with the standard backpacker setup in mind (snacks on the hips, shelter and water in the sides). This pack also features one of GG’s calling cards in a removable foam sitpad/frame with a beautiful large G printed on the front so everybody knows what brand your pack is. There are quite a few simplistic yet extremely helpful bells and whistles this pack has to offer so let’s get into it.

Gossamer Gear G4-20 Specs

Capacity: 42L
Weight: 25 ounces (including 3.3 ounce removable molded G sitpad)
Max Carry Capacity: 30 pounds
Materials: 70D and 100D (denier) Robic Nylon with DWR (durable water resistant) coating
Suggested Use: Thru-hiking, section hiking
MSRP: $180


  • Extendable roll-top with dual closure options (buckle down to sides or buckle around to self)
  • Waterproof zippers
  • Removable molded cushy sitpad/frame
  • Fixed hip belt with unique asymmetrical hip belt pocket design (one large standard zip pocket, one stretchy mesh pocket)
  • 1.5″ hip belt webbing for max comfort
  • Removable/adjustable side compression cord
  • Removable top compression strap
  • Small outer pocket with zipper at the top middle of pack
  • Asymmetrical side stretch pockets (right pocket standard for water bottles, left pocket extra tall for shelters and fits GG’s The One perfectly)
  • Two color options: Electric Blue and Titanium Gray
  • Three torso length options: Small, Medium, and Large



Conditions of Review

I’ve used this pack on hikes with extra weight and an overnight weekend trip in the Sipsey Wilderness in Northern Alabama in December 2019. I’ve tried to carry around 20 pounds each time I’ve taken this pack out, which is my average pack weight on the AT and PCT. The terrain was moderate (for Alabama) and I haven’t yet had the opportunity to put this pack to the test in the rain. My longest stretch of wearing this pack loaded without taking it off has been about 3.5 hours (~10 miles).


So far, I am thoroughly impressed with the comfort that this pack has provided, and I’ve been impressed by how little my shoulders hurt after long stretches without taking it off. I recently got accustomed to using a pack without a hip belt on the PCT and the transition back to having a hip belt is noticeable. Even without cranking down hard on the hip belt, I’ve been able to transfer enough weight off my shoulders that wearing this pack has felt mindless.

In addition to the comfort on my shoulders, I’ve been impressed with the comfort against my back. The 3.3-ounce foam sitpad used for the back panel is impressively cushy and feels nice against a sweaty back. It still isn’t quite as comfortable as a pack that offers mesh and space against the hiker’s back.

My Pack Experience, Compared

I’ve used four different packs throughout my thru-hikes but the two that I’ve put the most miles on compare well to the G4-20.

Zpacks Arc Haul

2,200 miles, AT
Weight: 23.3 ounces
Capacity: 62L
MSRP: $299

*with add ons (two hip pockets, one shoulder pocket, side compression straps)
25.9 ounces; $388

Mountainsmith Zerk 40

1,400 miles, PCT
Weight: 28 ounces
Capacity: 40L
MSRP: $219.95

What the G4-20 excels in is how handily it functions while also wearing comfortably. My favorite pack I’ve used recently is Mountainsmith’s Zerk 40, the king of handiness. It’s covered in stretchy pockets so you can access snacks and small items without taking your pack off. While I liked the Zerk 40, its lack of substantial hip belt did a number on my shoulders over the summer. In comparison, the G4-20 isn’t quite as handy (though it can be if you add GG shoulder pockets) but the hip belt keeps the shoulders at a much greater level of comfort, at least for me.

The other pack that I’ve put substantial miles on is the Zpacks Arc Haul, which is a pretty good comparison the G4-20. With the extra pockets I ended up getting on my Arc Haul, it ended up weighing more than the G4-20, but hardly a substantial difference. The biggest thing the Arc Haul has going for it is the frame. This feature was fantastic for letting my back breathe on the hot and humid AT. While the G4-20 doesn’t have a back panel that allows much breathing, the removable foam sitpad is comfortable against the back and is multifunctional. The extended side pocket on the G4-20 for holstering a shelter is a big deal. It’s such an efficient use of side space that I haven’t ever seen before. The mesh on the front pocket of the Arc Haul is fine enough that you could store your shelter there, but the items you’d be putting in that compartment would need to find a new home. Also, the Arc Haul is pricier than this pack.


This pack is designed with minor adjustments that are just substantial enough to make it feel like all your gear has the perfect home. Side pockets have always been a little awkward for me. One side is perfect for being able to reach back and grab my water bottle, but even after thousands of miles of backpacking I can’t figure out the best setup for the other side. This pack offers a really cool solution in an extended pocket to fit a shelter. It might be a bit tight for some two-person shelters, but for one-person shelters this thing is AWESOME. I’m a big fan of Gossamer Gear’s The One and it feels right at home in the side shelter pocket.

I’m also a fan of the stretchy mesh hip pocket. This is great for snacks and comfortably fits an iPhone 8+. I’d like to update the setup and add GG’s shoulder pockets, as I like having my phone up there, but in the meantime the hip pocket is a nice home. The pockets don’t stop there. There’s a zippered pocket above the front stretch pocket great for odds and ends (tent stakes, toiletries, extra snacks).

Finally, one of the big factors contributing to the handiness of this pack is the adjustability. The side and top compression straps can be removed if you find you don’t use them, as well as the side bungee-style straps. This pack is made to be used how it best suits the wearer.


This will be a an excellent pack for thru-hiking. It isn’t so small that you have to be extremely ultralight to make it work, but it’s small enough that you get to carry a lightweight pack. This pack seems durable enough to take a few thousand miles while keeping you comfortable and efficient on the trail. This pack would be great for anybody who has an “averagely lightweight setup,” basically any base weight under 20 pounds. For setups under 8-9 pounds this pack is probably too big, but for many hikers I think this is going to be just right.

Pros and Cons


  • Extremely handy (very efficient pockets and use of space)
  • Lightweight
  • Comfortable hip belt
  • Lots of good adjustability
  • Removable sitpad/cushy back support panel
  • Handy exterior zipper pocket
  • Affordable


  • My only significant gripe with this pack is the way that the hip belt adjusts. I’ve become accustomed to the straps adjusting where they attach to the pack. This strap adjusts at the buckle, which I find to be awkward and cumbersome. It’s not a huge deal, but I think this could be a little bit more user friendly.
  • The other improvement would be to include a shoulder-strap pocket. You can always add that modification when purchasing the pack, though.

Comparable Packs

I’d like to note that listed below are the VERY basic specs of each of these packs. This little information does not do them justice as each of these packs are highly varied.

Mountainsmith Zerk 40L
Weight: 28 ounces
MSRP: $219.95

Zpacks Arc Haul 62L
Weight: 23-26 ounces
MSRP: $299+

Gossamer Gear Gorilla 40L
Weight: 30.6 ounces
MSRP: $215

Hyperlite Mountain Gear 2400 Windrider 40L
30-32 ounces

Final Thoughts

This is an excellent all-around pack that is also extremely affordable. I will say that the functionality of it could definitely be in the eyes of the beholder. I think I have an “average” pack setup and pack in a “normal” manner, but it’s definitely possible to pick up this pack and not find much use in the asymmetrical pocket system. If you think this looks like the “perfect pack” for your setup, it just might be. If it looks too small/big for your setup and it feels like the pockets might be awkward for you, they probably will be.

Shop The Gossamer Gear G4-20 Here

**This product was donated for the purpose of review

Affiliate Disclosure

This website contains affiliate links, which means The Trek may receive a percentage of any product or service you purchase using the links in the articles or advertisements. The buyer pays the same price as they would otherwise, and your purchase helps to support The Trek's ongoing goal to serve you quality backpacking advice and information. Thanks for your support!

To learn more, please visit the About This Site page.

Comments 4

  • B.J. Clark : Jan 14th

    Lots to like about this pack, but you’re a braver person than me putting a phone in an open mesh pocket. I would lose it for sure!

  • James : Jan 17th

    I just got this pack and tested it out last weekend on an overnight on an unusually warm for winter New England weekend. I like it a lot. I am going to use it on a winter day hike this weekend in NH. The mesh pocket on the hip is a is a good place to stash gloves. The larger side pocket looks like it would be a good place to carry crampons and I am glad it has a ice axe loop. I agree with the hipbelt adjustment being awkward that was one of the first things I noticed.

  • : Feb 10th

    Devices that are outfitted with VoIP expertise can be used to make calls
    to phone programs which are located wherever on this planet.

    The price of VoIP phone systems has decreased many folds throughout final decade
    as a result of it uses shared sort of media with TCP/IP based protocol, which helps the users
    of this service to make use of transmission media very
    optimally. Well the last part of making choice is on you;
    you may both make investments one time on high quality helpdesk
    software program or can undergo from the sick effects occurring because of in poor
    health software. The first degree referred to as degree one specific assist facilitates customers utilizing fundamental considerations which is typically accomplished either over the telephone or through online means.
    This is often seen as an escalation from Level 1 IT help if the problem
    that needs resolving shouldn’t be a primary stage 1 IT concern. Each IT helpdesk request is issued a “criticality and response level” grading because it enters
    the job tracking system. As an illustration, if a
    helpdesk manager provides their clients a selection between rapidly resolving their problem on their very own and
    ready for help, believe it, the customers want to take the plunge.


What Do You Think?