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.
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.
Side-by-Side Comparison
Compare Black Diamond Beta Light 45 versus top competing products:
| Awards | |
|---|---|
| Price | $450 List Check Price at Backcountry |
Overall Score  |
|
| Star Rating | |
| Bottom Line | A running vest-inspired ultralight pack that's clearly designed to move fast and light |
| Pros | Modular design, running vest-style shoulder straps, much larger capacity than its size suggests |
| Cons | Expensive, limited external lash points, comfort drops as weight increases |
| Rating Categories | Black Diamond Beta L... |
| Comfort (40%) | |
| Ease of Use (25%) | |
| Weight-to-Volume Ratio (20%) | |
| Adjustability (15%) | |
| Specifications | Black Diamond Beta L... |
| Measured Weight | 31.7 oz |
| Stripped Weight | 19.0 oz |
| Advertised Volume | 45 L |
| Measured Volume (Main Compartment) | 40 L |
| Weight per Liter (Full Pack) | 0.70 oz/L |
| Sizes Available | Torso: XS, S, M, L |
| Organization Compartments | Side pockets, center pocket, dual zippered pockets on hip belt, main compartment |
| Hydration Compatible | Yes |
| Side Pocket 700ml Smartwater Capacity | 5 |
| Single Hip Belt Pocket Capacity | 5 Clif Bars |
| Removable Frame and Hip Belt | Yes |
| Sternum Strap Whistle | No |
| BearVault BV500 Compatibility | Good |
| Frame Type | 2 removable stays, thin foam padding |
| Fabric | Ultra 200, Ultra 400, 4-way stretch mesh, 100D nylon 4 mm ripstop |
—Justin Simoni
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