REASONS TO BUY
Modular design
Running vest-style shoulder straps
Much larger capacity than its size suggests
REASONS TO AVOID
Expensive
Limited external lash points
Comfort drops as weight increases
Black Diamond Beta Light 45 Review
A running vest-inspired ultralight pack that's clearly designed to move fast and light
The Black Diamond Beta Light 45 is a fastpackers dream, with comfortable, running-vest-inspired straps and plenty of capacity.
Credit: Justin Simoni
By Justin Simoni ⋅ Review Editor ⋅ June 10, 2026
RELATED: The Best Ultralight Backpack of 2026
Our Verdict
Inspired by both trail-running vests and cottage-industry brands, the Black Diamond Beta Light 45 is the first pack from a major brand that uses the exceptionally lightweight, durable Challenge Ultra 200 fabric. A 40-liter main compartment is complemented by large side and center pockets that offer an additional 15 liters of storage. A modular design starts as a 32-ounce pack, but if you strip the Beta Light of some accessories – like the hip belt and interior frame stays – the base weight comes down to a very respectable 19 ounces. The running vest-style straps do a good job carrying a load up to 40 pounds, though, as a pack specifically designed for fast and light trips, lighter loads are more comfortable to carry.
Compare to Similar Products
 This Product
Black Diamond Beta Light 45 | |||||
|---|---|---|---|---|---|
| Awards |  Best Overall Ultralight Backpack |  Best Bang For Your Buck |  Best Full-Featured UL Pack | Best Pack for Expert Ultralighters | |
| Price | $450 List Check Price at REI | $315 List | $279 List | $330 List Check Price at REI | $350 List |
Overall Score  |
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| Star Rating | |||||
| Bottom Line | A running vest-inspired ultralight pack that's clearly designed to move fast and light | This pack wowed us with its perfect set of features, comfortable design, and impressively large carrying capacity | A tough, voluminous, and reasonably priced ultralight backpack that's perfectly designed for long trips | An excellent pack for those who want to move up from a conventional backpack, but don't want to lose out on creature comforts | When it comes to frameless ultralight packs, this one leads the way in weight, design, and innovation |
| Rating Categories | Black Diamond Beta L... | Gossamer Gear Maripo... | Durston Kakwa 55 | Osprey Exos Pro 55 | Nashville Pack The C... |
| Comfort (40%) | |||||
| Ease of Use (25%) | |||||
| Weight-to-Volume Ratio (20%) | |||||
| Adjustability (15%) | |||||
| Specifications | Black Diamond Beta L... | Gossamer Gear Maripo... | Durston Kakwa 55 | Osprey Exos Pro 55 | Nashville Pack The C... |
| Measured Weight | 31.7 oz | 34.3 oz | 31.0 oz | 33.2 oz | 22.0 oz |
| Stripped Weight | 19.0 oz | 18.0 oz | 27.5 oz | 30.4 oz | 17.3 oz |
| Advertised Volume | 45 L | 60 L | 70 L | 55 L | 40 L |
| Measured Volume (Main Compartment) | 40 L | 54 L | 55 L | 46 L | 43 L |
| Weight per Liter (Full Pack) | 0.70 oz/L | 0.57 oz/L | 0.44 oz/L | 0.60 oz/L | 0.40 oz/L |
| Sizes Available | Torso: XS, S, M, L | Torso: S, M, L Hip Belt: S/M Curved (w/ S torso), M Straight (w/ M and L torso); other hip belts sold separately |
Torso: S, M, L Hip Belt S/M, M/L |
Torso: S/M, L/XL | Torso: 16', 18", 20" Hip Belt: S (28"-38"), M (32"-42"), L (26"-48") Should Straps: 16", 17.5", 19", 20.5" |
| Organization Compartments | Side pockets, center pocket, dual zippered pockets on hip belt, main compartment | Top flat zippered pocket, three total side pockets, center pocket, dual zippered pockets on hip belt, main compartment | Side pockets, side zipper pocket, center pocket, hip belt pockets, strap pockets, main compartment | Lid, mesh side pockets, center pocket, dual zippered pockets on hip belt, main compartment | Main compartment, center pocket, running vest-style pockets, back-entry bottom stash pocket |
| Hydration Compatible | Yes | Yes | No | Yes | No |
| Side Pocket 700ml Smartwater Capacity | 5 | 3 | 3 | 5 | Continuous wraparound pocket |
| Single Hip Belt Pocket Capacity | 5 Clif Bars | 6 Clif Bars | 10 Cliff Bars | 4 Clif Bars | N/A |
| Removable Frame and Hip Belt | Yes | Yes | No | No | Yes |
| Sternum Strap Whistle | No | Yes | No | Yes | No |
| BearVault BV500 Compatibility | Good | Good | Excellent | Good | OK |
| Frame Type | 2 removable stays, thin foam padding | Removable SitLight foam pad / removable stay | Removable foam pad / removable stay | 3.5 mm powder-coated LightWire frame | None |
| Fabric | Ultra 200, Ultra 400, 4-way stretch mesh, 100D nylon 4 mm ripstop | 100D & 210D recycled Robic nylon | Challenge Ultra 200x | NanoFly: 100D nylon x 200D UHMWPE ripstop | 210D Venom Gridstop ECO |
Our Analysis and Test Results
The Challenge Ultra 200X, which makes up the bulk of the Beta Light 45, is the same material you find on other high-end, ultralight packs. This fabric is water-resistant and incredibly durable. The adaptability of this pack is hard to match: many parts can be removed to drop weight, turning this thru-hiking hot rod into a nimble day pack.
The Black Diamond Beta Light 45 is ready for long day trips, long weekend segment hikes, and cross-country treks. Credit: Justin Simoni
Likes
The Beta Light 45 is one of the most comfortable packs we tested for carrying small to medium-sized loads.
Its running-vest-inspired design features wide shoulder straps and dual sternum straps that hug the pack to your body, evenly distributing the weight across your shoulders.
A big part of moving quickly is feeling comfortable. The Beta Light 45's design hugs your entire upper body. Credit: Justin Simoni
But unlike a running vest, this pack has an internal frame, back padding, and a wraparound hip belt to provide further support for heavier loads. We took to the Colorado Trail for a fastpacking trip with the Beta Light 45, and even with extra gear, like snowshoes, we were quite comfortable carrying the extra weight.
The internal frame helps support weight and ensure that a properly loaded pack stays securely against your back. Credit: Justin Simoni
Modularity is also a big plus for the Beta Light 45. More than most other packs we've tested, it's easy to strip this pack of certain components to lighten the load or customize your needs for a given trip. By removing the internal frame, back padding, hip belt, and various straps, we were able to cut the Beta Light 45 down to an impressive 19 oz.
The pack's modularity makes it more versatile, easily transitioning from a thru-hiking fastpack to a very capable mountaineering pack.
The Beta Light 45 also features a ton of external storage options. It features running-vest-style shoulder-strap pockets for easy access to small essentials, and bottom lash points for carrying bulkier gear like closed-cell foam pads and even snowshoes.
Having quick yet secure access to gear outside our pack saves us time by avoiding the need to open the main compartment.
Dislikes
Even though its carrying capacity would make it easy, overloading the Beta Light 45 is a sure way to fall out of love with this backpack. One issue is that the vest-style shoulder straps are slightly stretchy, and as the pack weight increases, the pack starts to bounce. The hip belt does a fair job of distributing weight to the hips, but, like the shoulder straps, it becomes less effective as weight increases.
The Beta Light 45 is much heavier than similarly sized packs. An advertised volume of 45 liters and a base weight of 31.7 ounces gives us a ratio of 0.70 oz/L – this passes our cutoff for an “ultralight” pack, but it's right on the cusp. Black Diamond says this pack can carry up to 40 lbs, but that's pushing it, in our opinion.
You could carry a bear canister using the single top strap, but it's not very secure. Credit: Justin Simoni
Should You Buy the Black Diamond Beta Light 45?
The modular design of the Beta Light 45 doesn't fit into just one box. Whether you're gearing up for a fastpacking overnighter, a spring mountaineering adventure, or a transcontinental thru-hike, this pack can adapt to your needs. It's an expensive jack-of-all-trades, but considering its versatility and durability, the investment is well worth it – it's certainly one of the best running-vest-style ultralight packs we've tested.
What Other Ultralight Backpacks Should You Consider?
The 55-liter Six Moon Designs Swift V is another running-vest-style pack that's one of our favorites for long trips – it's much cheaper than the Beta Light 45, too. Even though the Durston Kakwa 55 doesn't have the same running-vest-style shoulder straps, it's another high-capacity pack that outperforms either the Swift V or the Beta Light 45, making it the best bang for your buck.
—Justin Simoni
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