The Photon: Minimalist Versatility

WEIGHT: 26.1 OZ | 740 GM 

VOLUME: 2,150 CU IN | 35 L

MAX LOAD: 25 LBS | 11.34 KG

Total External Pockets not including hip belt pockets: 3

Water bladder compatible: Robic Only

The ULA Photon is our most compact ultralight pack, coming in at around 35 liters of total volume. It’s built for hikers who’ve stripped their gear list down to the essentials—those who have a base weight under 10 pounds and know exactly what they need and nothing more. The Photon excels in short overnight trips, weekend loops, and fast-and-light missions. Its streamlined shape and external organization also make it a solid choice for adventure travel or everyday carry. We’ve deemed it the “little brother” of the CDT pack because it has the exact same feature set and pattern as the CDT, just in a smaller size.

It’s important to note here that while the Photon is great for smaller loadouts, if you put too much gear into it, the back panel can start to bow out making it uncomfortable and impractical for longer excursions like section hikes and thru-hikes. Given it has no frame, the way you pack your bag will make all the difference on how well it carries for you.

Despite its smaller size, the Photon still delivers smart features. The roll-top closure gives you adjustable capacity, while the removable Y-strap on top helps secure bear cans or bulky layers. Like most of our packs, the Photon gives you the option to add or remove a hip belt depending on your trip and comfort needs. This is a great way to make sure your pack fits you correctly as the throws of life see you gaining or losing weight over time.

The Nexus: Crossover Innovation

WEIGHT: 18.8 – 22.3 OZ  | 533 – 632.2 GM 

VOLUME: 2,441 CU IN | 40 L

MAX LOAD: 25 LBS | 11.3 KG

Total External Pockets not including hip belt pockets: 5-6 depending on if you add the bottom pocket.

Water bladder compatible: No

The Nexus sits between the Photon and CDT in volume, but carves out its own identity in design, layout, and intention. It’s a 40-liter frameless pack with a more modular and technical approach, suited for people who like to have additional storage and organizational options. One of the standout features on the Nexus are the side utility pockets made of UltraStretch mesh, which aren’t available on any other pack in our line up – you can however add them to other stock packs for a custom order. Additionally, the Nexus was intentionally designed to be wide enough to carry a BV500 vertically inside of the pack, and you can also add a bottom pocket for additional on-trail flair.

The Nexus features a sewn-in top Y-strap as well as a sewn-in hip belt to save weight. The hip belt pockets on the Nexus are a new design that enables you to zip/unzip them with one hand while on the move and are structured to give you enough storage space to fit contemporary cell phones while fit to a smaller wing so they stay out of the way when moving fast.

Offered in 210 UltraGrid and 200X UltraWeave, the Nexus is our most advanced frameless pack we offer from its feature set to its fabrics.

The Nexus is for people who want ultralight performance, but who also need smart access. It’s ideal for fast-moving adventures that require packing efficiency, technical carry, or mixed terrain. 

Contrary to the CDT and Photon, the Nexus is offered in 3 shoulder strap styles, our traditional S + J straps, and a new hybrid straps that straddles between the two.

The CDT: The Ultralight Classic

WEIGHT: 27.1 OZ | 768 GM – 19 OZ without hip belt

VOLUME: 3,370 CU IN | 54 L

MAX LOAD: 25 LBS | 11.34 KG

Total External Pockets not including hip belt pockets: 3

Water bladder compatible: Robic Only

The CDT has earned a strong reputation among ultralight thru-hikers, and for good reason. With a capacity of about 54 liters, it’s the largest frameless pack we make and can handle everything you need for a long-distance hike—as long as your kit is dialed. It’s designed for simplicity: a large main compartment, a spacious front mesh pocket, and roll-top closure give you everything you need and nothing you don’t.

The CDT is a true frameless workhorse. It’s made to be packed efficiently—using your sleeping pad or gear to create structure—and rewards experienced hikers who’ve mastered smart packing. The added volume compared to the Photon makes it more forgiving on longer carries or in variable weather when extra layers, food, or insulation are required. For ultralight hikers who still want room to breathe, the CDT is the sweet spot. 

Just like the Photon, the CDT has a removable and height adjustable hip belt making it a great option for those in between sizes.

Garrett uses a Large torso CDT and can comfortably fit a BV500 inside vertically(don’t tell Peter). That’s all to say, if you’re tall and really have your shit together, the CDT offers more than enough space for your gear. Alternatively, you can always use the removable top Y-strap to lock down the bear canister.

This pack’s DNA is pure trail. It’s designed to disappear on your back, stay quiet, and keep moving through big miles. The removable hip belt lets you go fully stripped-down if needed, while side compression straps help keep loads tight and controlled. If you’re heading out on a thru-hike or want a minimal but spacious pack that will hold up for thousands of miles, the CDT is the one.

Shared DNA: What All Three Packs Have in Common

Though each of these packs has its own strengths, they all share ULA’s core philosophy—ultralight doesn’t mean ultra-fragile. All three models are frameless, meaning they rely on your packing technique and gear arrangement for structure. When packed well (with a foam pad, tightly stuffed sleeping quilt, or clothing layers providing shape), these packs ride close to your body, keep weight tight to your center of gravity, and feel natural to wear over long distances.

They all use roll-top closures for streamlined weather protection and compression, offer optional/removable hipbelts for customization, and feature hydration sleeve compatibility. And they’re all made in the USA by a team of real hikers and gear nerds who’ve tested these designs in the field. 

All 3 have cinchable side pockets designed for 1 liter SmartWater bottles. The CDT and Nexus can comfortably fit 2 bottles of this size in each pocket while the Photon is better served with just one. 

All of our shoulder strap styles on these three packs are compatible with all ULA Shoulder Strap Accessories.

All models also feature removable front shock cord, Ice-axe loops, haul loops, and adjustable sternum straps.

Fabric Options: Durability, Weight, and Real-World Function

One of the most important considerations when choosing between the Photon, CDT, and Nexus is the fabric. Materials shape not only how a pack holds up to trail abuse, but also how it carries, sheds water, and wears over time. Each of these packs is offered in distinct fabric options to meet different needs and budgets—ranging from dependable Robic nylon to cutting-edge UHMWPE composites.

And importantly: all fabric options offered for these packs are PFAS-free, meaning they’re free from harmful “forever chemicals” often used in water-resistant coatings. ULA is committed to reducing environmental impact without compromising on performance.

Photon and CDT: 420D Robic or Ultra 200X/400X 

Both the Photon and CDT are available in either 420D Robic nylon or a Ultra 200X/400X configuration:

• 420D Robic is a tried-and-true high-tenacity nylon. It’s tough, abrasion-resistant, and relatively affordable, making it ideal for thru-hikers and weekend warriors alike who want reliability without overcomplicating things. It’s slightly heavier than composite options but known for its forgiving nature and soft hand-feel.

• Ultra 200X/400X is a hybrid construction that strategically uses different fabric weights based on abrasion zones. Ultra 200X—a woven UHMWPE laminate—is used in low-wear areas to reduce weight. Ultra 400X is deployed in high-abrasion zones (like the bottom panel and pockets), offering double the tear and abrasion resistance while still maintaining an ultralight profile. This targeted durability approach ensures strength where it matters most without adding unnecessary grams.

This combination gives CDT and Photon users the best of both worlds: premium materials with thoughtful design for long-term trail use and serious mileage.

Nexus: 210D UltraGrid or Ultra 200X

The Nexus is also available in Ultra 200X, but has a second option with 210D UltraGrid, a high-performance, sustainable fabric that blends functionality with a modern aesthetic.

• UltraGrid is made from 100% recycled nylon yarns and reinforced with a UHMWPE ripstop grid, delivering a strong, abrasion-resistant surface that’s noticeably lighter than Robic but still highly durable. A UTS coating adds water resistance without the slick feel of PU. It’s a great option for ultralighters looking for performance without going full composite.

• Ultra 200X, shared with the CDT and Photon, is the top-tier option. If you want maximum strength and weather resistance in a minimalist, urban-ready form, the Nexus in Ultra 200X is as premium as it gets in this weight class.

Bottom line: If you want the most affordable and field-proven option, 420 Robic gets the job done and then some. If you’re ready to invest in cutting-edge materials with exceptional strength-to-weight ratios and waterproofness, Ultra X is available across all three packs. While UltraGrid offers a durable, good-looking middle ground with sustainability in mind.

For more on Ultra fabrics vs Robic – read this.

Which Pack Is Right for You?

If you’re doing overnight trips, traveling light, or want a pack that can handle some peak bagging without the extra fabric or frame as some other day packs out there, the Photon is your best bet. It’s the most compact and the easiest to use in a variety of settings beyond the backcountry. If you plan on doing more than a few nights out, go with the Nexus or the CDT.

If you’re planning a long-distance thru-hike, or you want the most internal space possible without moving into a frame-based pack, the CDT is a proven classic. It offers the volume and layout long-haul hikers need while still encouraging you to keep your kit minimal. While it’s a little heavier than some packs in its size category, it more than makes up for it in comfort with the adjustable hip belt and our tried and true shoulder straps.

And if you’re a true ultralight freak – or if you value access, internal organization, and versatility, the Nexus is the modern answer to ultralight, multi-environment carry. If you’re no bones about it and pretty cut and dry about wanting the lightest and most versatile pack we offer, the Nexus is what you’re looking for.

Final Thoughts

The right pack is the one that fits your style, your gear, and your miles. Whether you’re going for a smaller overnighter experience with the Photon, the bigger-mile focus of the CDT, or the modern utility of the Nexus, each of these packs reflects a different way to approach ultralight.

At the end of the day, they’re all built on the same foundation—simplicity, durability, and thoughtful design. Strip it down, load it right, and hit the trail with confidence. Every cat hole has its day.