Moment Fast and Light 4L Sling Review: The Perfect Balance of Function, Comfort, and Capacity

Fit and Comfort

Right off the bat, the fit is one of the best things about the Fast and Light 4L Sling. It’s designed to be worn either across your body as a sling or around your waist like a fanny pack — and it feels great in both configurations.

The back panel is breathable padded mesh which keeps the back nice and cool on hot days. What really stands out, though, are the side wings — also padded and made of the same breathable mesh material. These wings contour nicely to your body and help distribute weight evenly across the upper body, especially when wearing the sling in waist pack mode. It’s a small design detail, but it makes a big difference in comfort (which is a must if I'm out and about).

The strap is decent — not super fancy or premium-feeling, but functional and comfortable. It meets that everyday middle-class, where it’s just wide enough to distribute weight well and doesn’t dig into your shoulder. Compared to the smaller 1.5L version, the 4L’s strap is noticeably wider, which is a nice upgrade for the additional weight this bag can carry.

But if I had to nitpick, I do wish the strap used a smoother, seatbelt-like material, even the Everything Bag line sports this touch. It would glide better when adjusting and feel more a little more luxurious in hand. But overall, the fit and comfort of this sling are excellent for its size and outside-forward purpose.

Front Compartment

One of my favorite external details is the stretch mesh front compartment. It’s super flexible, easy to access, and perfect for items you want to grab quickly — sunglasses, gloves, or a small snack. The stretch mesh expands generously but still keeps a low profile when empty, maintaining the bag’s sleek aesthetic.

It’s minimal in theory but highly useful, which is exactly what a front pocket on a small sling should be.

Main Compartment

Open up the main compartment, and the first thing that jumps out is the salmon pink interior lining. I love this choice. Not only does it add a pop of personality, but it also makes your interiors stand out, which helps a ton when you’re trying to find small accessories or dark-colored items in low light.

In terms of space, this compartment is surprisingly roomy. I can easily fit a Fujifilm X100VI with a wallet beside it — and still have space left for other essentials. It’s the perfect size for an everyday carry setup or a compact camera travel kit.

Moment included plenty of internal organization here:

• Two small padded slide pockets — nice for filters or other small EDC items.
• Two larger stretch mesh pockets — great for things like AirPods, spare batteries, or cables.
• A large rear slide pocket — ideal for flatter items like a phone, travel documents, or wet wipes.

There’s also a key leash, which is a nice touch — though I really wish it were longer. Right now, it’s a bit short, making it slightly awkward to use if you’re trying to unlock something without fully removing your keys.

Overall, the main compartment is where this sling truly shines. It’s intelligently organized, spacious for its size, and lined with high-visibility material that makes packing and accessing gear effortless.

Back Compartment

On the back, there’s a zippered compartment that’s fairly slim but great for slimmer things — perfect for storing cash, a passport, or flat papers.

Exterior Design and Utility

Moment clearly designed the exterior of the 4L Sling with outdoor functionality in mind. Both sides of the bag feature dual stretch mesh stash pockets, which are surprisingly handy. They’re perfect for smaller items like snacks, gloves, or even a short water bottle.

To help secure those bottles, there are bungee cords on either side — a smart addition that keeps things from falling out while moving around.

On the bottom of the sling, you’ll find two additional bungee cords that can hold a small jacket, compact umbrella, longer water bottle, or even a lightweight tripod. This gives the bag an impressive amount of flexibility for its size — especially for hikers or photographers who like to carry a few extras.

There’s also a stabilizer strap, which helps keep the bag snug against your body when you’re moving fast or biking. The bottom panel is slightly padded as well, which adds protection if you’re carrying a small camera inside. It’s not overly thick, but it’s enough to give you confidence setting the bag down on harder surfaces.

Overall, the exterior is thoughtfully designed and highly functional. It feels rugged, versatile, and ready for whatever the day brings.

Strap and Hardware

The strap setup is where things get a bit interesting — and slightly inconsistent compared to other Fast and Light slings. The 4L version features a push-release buckle, but it’s located on the opposite side from where it is on the 1.5L sling. It’s not a dealbreaker, but it can throw you off if you’re used to one orientation over the other.

As mentioned earlier, I really appreciate the wider strap, which improves comfort and stability, especially when carrying heavier loads. However, the material itself could be better. A seatbelt-style strap would level up the feel and make adjustments smoother.

Another improvement I’d love to see is a push-release buckle on both sides. That would give users more flexibility for how they wear and adjust the sling, especially when switching between left and right shoulder carry.

It’s a small change that would make a noticeable difference in usability.

Areas for Improvement

No bag is perfect, and while the 4L Sling hits most of the right notes, there are a few tweaks that could make it even better.

• Key leash length: Too short — just needs a couple more inches of reach to be truly convenient.
• Main compartment zipper: A waterproof zipper would have been a great upgrade, especially since this is designed as an outdoor sling.
• Bottom bungee hooks: The current hook-style attachment works, but it’s not the fastest system. I’d much prefer a small push-release buckle for quicker access and more secure fastening.
• Dual-side buckle option: As mentioned, having a release buckle on both sides would make it more adaptable for different carry styles.

None of these are major flaws, but they’re small refinements that would take the bag from great to nearly perfect.

Final Thoughts and Rating

After plenty of real-world use, the Moment Fast and Light 4L Sling has earned its spot as one of my favorite compact carry options. It’s comfortable, functional, and incredibly versatile, striking an ideal balance between size and utility.

It’s just large enough to carry a small camera setup plus daily essentials, yet small enough to wear all day without feeling bulky. The breathable, padded design makes it easy to forget you’re even wearing it, and the thoughtful organization keeps your gear neatly in place.

There’s definitely room for improvement — particularly in the strap design and some minor hardware choices — but none of these issues overshadow what’s otherwise a very well-executed sling.

If I had to rate it, I’d give the Moment Fast and Light 4L Sling an 8.5 out of 10.

It’s a near-perfect balance of comfort, organization, and adventure-ready design — a great choice for anyone who wants a lightweight, do-it-all sling that can go from city streets to mountain trails without missing a beat.