Aer Day & City Slings: Review

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Aer, out of San Francisco, has been one of the hottest bag makers in the industry for a good minute. With slick styling, quality materials, and carefully considered designs, Aer bags find themselves at home from the tarmac and the office to the gym and the streets. Slings are the current big trend in carry, and with the Day and City, Aer has thrown their hat in the ring, and it is a very nice hat.

This Day Sling is specifically labeled as the Day Sling 2 – the second iteration of this product. While the City Sling is a brand new offering, first teased through a collaboration with Oshmans. With similar branding, these seem relatively similar at a glance, but that couldn’t be further from the truth. Let’s dive in and see which might work for you.

Tech Specs

Day Sling

Height6″15 cm
Length12.5″32 cm
Depth3″7.5 cm
Capacity275 cu. in.4.5L
Primary Materials1680D Codura, YKK Zippers

City Sling

Height4.5″11.5 cm
Length12.5″32 cm
Capacity146.5 cu. in.2.4L
Primary Materials1680D Codura, YKK Zippers

Quality and Comfort

Both the Day and City slings are made with 1680D Cordura, which is a lighter weight Cordura than you’d think given the denier. The weave gives it an almost luggage-like appearance. I’ve never known Aer to skimp on materials. Both bags have a mixture of YKK standard and Aquaguard zippers, depending on the compartment, and all zippers are adorned with Aer’s signature pulls, which are kind of love-it-or-hate-it. They’re big and easy to grab, but they also dangle off these little bags like Christmas ornaments.

Aer Day Sling front

The first thing that stands out about the Day sling is the way it carries. Unlike almost all other slings on the market, one strap attaches at the side, horizontally, while the other attaches at the top, vertically, with a large buckle. This makes for not only a more comfortable carry, but it lets the bag line up horizontally across your chest. This makes for excellent ambidextrous entry, but it does require you to carry your bag over your left shoulder, and slung under your right. Personally, I love it. The only downside I encountered with this setup is that since it doesn’t hold as tightly across your chest, and instead kind of hangs, it’s bound to bounce around a little if you’re running to catch your next plane.

Aer Day Sling wearing

The City sling takes the strap setup in a different direction, which might be better for some and worse for others. It’s a very tradition hip pack setup, with both straps connecting horizontally and the buckle meeting in the middle. I’m not a huge fan of this setup, especially given the novel setup of the Day sling. I believe that slings should be one-hand adjustable, which means they need a semi-fixed end and an adjustable end with most of the strap length.

Aer City Sling strap

On top of this, whether you have the City slung across your back or chest, the centered buckle is kind of in an awkward place. As an example, if you’re taking transit or driving with the City across your chest, the buckle is just going to dig in your back, even if you have it adjusted as far as you can to a single side. If there’s ever a City Sling 2, I’d like to see some fine tuning around this, or maybe just even marketing it as a hip pack instead. The buckle-in-the-back problem could also be alleviated by a less substantial buckle.

Aer City Sling wearing

Another place where the City and Day differ is that the City sling comes with some built in expansion / compression. It’s very similar to the Bellroy Sling, but it adds something I wish the Bellroy Sling did have – lock out compression. This system also ends up letting the City sling carry larger, bulkier items than the Day sling, despite the slightly smaller footprint.


The pocket setup on both slings is relatively similar. Both have a front compartment, a main compartment, and a hidden rear compartment. All using a mix of YKK zippers in various forms.

Aer City and Day slings

The front compartment of the Day sling is secured with a YKK Aquaguard zipper – the only one on the bag. Each side is flanked by a pull-tab, since Aquaguard zippers tend to be a slight bit more difficult to slide. Inside there are two extra elastic-top pockets. This area also has it’s own volume, which is a nice plus on an already slim bag.

Aer Day Sling front pocket

The main compartment has all sorts of organization – something I appreciate on a bag this size, since it’s difficult to bring your own organizers. Like the front, there are two elastic-topped pockets of similar size. Behind that is a zippered pocket taking the whole length of the bag, and behind that is another full-length sleeve. I really like the organization provide by the Day, but unfortunately since it’s such a slim bag, you really can’t fit much in here outside of similarly slim items.

Aer Day Sling main compartment

Both the Day and City have a rear-facing pocket secured by a YKK zipper. This compartment is basically invisible while you’re wearing the bag, so it’s a great place to keep valuables, like a wallet or passport. Personally, I’d recommend removing the zipper pull from here to keep it more secure.

Aer City and Day slings rear pocket

The front pocket of the City sling is also secured by a YKK Aquaguard zipper – still the only one on the bag. It’s a slimmer pocket than on the Day, and doesn’t have any further organization aside from a key leash, which the Day does not have.

Aer City Sling front pocket

The main compartment of the City sling is nice and spacious. It has a similar pocket setup to the Day, except divided into the front and rear of the compartment rather than all being towards the rear. And, as mentioned above, the boxier shape of the City, coupled with it’s compression system, really lets you load it up a good bit more than the Day, especially if you tend to carry bulkier items, like a mirrorless camera.

Aer City Sling main compartment

What’s Perfect

Day Sling

  • Great built-in organization.
  • Super comfortable sling setup – maybe the best I’ve ever used
  • Great price point @ $65.

City Sling

  • Great built-in organization.
  • Expansion / compression is great for carrying bulkier items or slimming it down when not.
  • A bit more expensive, but still not bad @ $75.

What’s Not

Day Sling

  • Slim profile without any expansion starts to fall flat when you want to carry larger or bulkier items.
  • The sling setup could lead to some bouncing around.
  • The zipper pulls are overkill.

City Sling

  • Sling setup is more akin to a hip pack which makes the buckle positioning and adjustment awkward when trying to use as a sling.
  • The zipper pulls are overkill.

Wrap Up

These two slings from Aer are a couple of the most popular slings today, with both selling out as soon as Aer is able to stock them. There’s a reason, and it’s because they’re both really solid sling offerings. However, they’re more different than you’d be led to believe.

It’s common to see recommendations between the City and Day simply based on size, but that’s not really a great way to differentiate between these two. The City and Day share a very similar size footprint, but they couldn’t be more different in how they carried and what they can hold. If you’re looking something a bit more traditional, yet refined, the City sling might be up your alley with it’s double-ended strap and expansion system. If you’re looking for something a little out of the norm that’s comfortable to carry for hours between your vehicle and transit to the local dive, then the Day might be your huckleberry.

Personally, my perfect sling might exist somewhere between these two, with the suspension of the Day and the expansion of the City – but for now you’ll have to make a choice.

Aer City and Day slings

The Day and City slings both come in Aer’s standard offerings of fabrics and are available from Aer directly for $65 and $75 respectively.

Editor’s Note: The City and Day slings used for this review were provided by Aer. Our reviews are impartial, and the content of this review was not discussed with Aer prior to publication.

1 comments on “Aer Day & City Slings: Review”

  1. i have a bad experience with the city sling I like to have it in front of my chest thinking it’s the safest place with the big buckle around my back I got robbed in Phnom Penh because the buckle is so big this guy pulled up behind me in scooter unbuckle the sling and rode off I like to see a smaller buckle and to the side like day sling 2 its much safer


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