Last year, I tested the USWE Outlander XC alongside several other cycling hydration vests. While the Outlander isnt technically a vest, its compact size and No Dancing Monkey harness design are fairly close. But with limited storage and no chest pockets, its perhaps not as vest-like as the competition, comparatively speaking. So, at Sea Otter, I swung by the USWE booth to see if they had anything new or interesting to check out.Thats where I learned about the new USWE Vest VST, a true hydration vest designed to meet the demands of trail runners and cyclists alike. It is lightweight with a streamlined fit and 8 liters of storage capacity spread between its back and chest pockets. Arguably one of its most interesting features is its compatibility with either a 2L water bladder for cycling or 0.5L chest pocket soft flasks for running, or both at the same time. When purchasing, buyers can configure their Vest VST to suit their needs and preferences.I got my hands on the USWE Vest VST in a cycling-oriented configuration with a 2L bladder and insulated bladder sleeve, and Ive been riding and running for the past couple of months. Its the most vest-like (vestiest?) hydration vest that Ive ever worn, impressively stable, and Ive found that it performs well whether Im bouncing down the trail on my feet or on my mountain bike.USWE Vest VSTCheck Price at REISpecificationsMSRP: $135 (vest only), $189 (w/ bladder)Weight: 253 g (vest only), 162 g (bladder and sleeve)Storage capacity: 8 LFront pockets: 1 zippered and 3 stretch (per side)Water capacity: 2 L bladder and/or 2x 0.5 L soft flasksSizes: XS, S, M, L, XLFit adjustments: Adjustable elastic side strapsColors: Black, White, BronzeProsSuper stableVery comfortableFairly lightweightVersatile works great for trail running, tooTons of cargo spaceYou pick the hydration system that works best for youConsKinda expensiveHydration system costs extraFive sizes measure chest/try on to find the right fitPerhaps too many pockets on the frontJeremy BensonVest VST DetailsNo Dancing Monkey is what USWE calls its harness system, and it has a fairly unique design compared to other hydration vests.The Vest VST uses USWEs No Dancing Monkey (NDM) harness technology. This involves more of an X-like design with a single, circular buckle in the center to quickly and easily secure it at the chest. The front straps and shoulders are made from an open, airy, breathable mesh with a finer mesh covering the back panel. Overall, this construction gives the pack very little structure. In that regard, it is quite similar to the superlight Velocio Hydration Pack.Lots of mesh against the body.On the chest, sides, and back, the mesh backing is topped with both mesh pockets and a stretchy polyester/spandex exterior fabric. This stretch material is used for the outermost front/chest pockets as well as the larger storage pockets on the back. On the upper back, USWE also included a Recco reflector for search and rescue situations. The VST comes in three tasteful colors, including black, white, and bronze. Although white will probably get dirty with dust or mud fairly easily, I suspect it might help keep your fluids a tiny bit cooler for longer. Additionally, the VST has reflective logos on the back, sides, and left chest to enhance low-light visibility.The side panels have elastic cords which can be used to adjust the fit.Sizing and FitThe Vest VST comes in five sizes, XS to XL, each of which fits a small range of chest sizes. This five-size range should make it so that users within the fit range can find a relatively snug fit right out of the gate. Elastic cords on both sides of the torso offer a little adjustability to optimize the fit.Its worth mentioning that the Vest VST sizing does not mirror that of shirt sizes, so its important to check the size chart and measure your chest circumference to see where you land. For example, I wear a medium bike jersey, but my 39 chest measurement puts me squarely in a large USWE Vest VST, which Ive found to be a perfect fit.Modular HydrationOne of the more unique features of the Vest VST is that it is designed as a crossover vest for running and/or cycling, and it works with two different hydration systems. You can choose to use it with either a 2L water bladder and hose, two 0.5-liter soft flasks in the chest pockets, or even both at the same time. Mountain and gravel cyclists will likely gravitate toward the bladder, trail runners may prefer the soft flasks, and some multi-sport athletes might spring for both and switch between them.The hydration bladder has a quick connect fitting for the hose with a standard bite valve with a locking, on/off switch.USWE sells the VST on its own for $135, and when purchasing directly from the brand, buyers can choose their preferred hydration methods. The 2L hydration bladder goes for $45, and the insulated bladder sleeve adds another $15. When buying from other online retailers, like REI, for example, the Bike VST 8L Hydration vest comes with all of the above for $189.The VST running setup with the soft flasks with straws. (photo/USWE)For the runners, USWE offers two types of soft flasks for the chest pockets. They come in sets of two, with straws for $44, or with the wide-opening tops for $54. USWE also sells Torr Drysacks in 2L ($22) and 8L ($28) sizes.StorageMy Patagonia Trail Craft Jacket fits easily in the top-loading zip pocket on the VST.According to USWE, the Vest VST has 8 liters of total capacity. Thats somewhat surprising given its relatively sleek and streamlined shape and profile, but its looks are deceiving. Theres a fair amount of stretch in the outer shell fabric, allowing the back and chest pockets to expand and fit quite a bit of gear.The bottom-loading pocket is where Ive been stashing my tools, tubes, etc. The bulk of the storage space is divided up between two large zippered pockets on the back, one top-loading and one bottom-loading, plus the large drop-in sleeve for the water bladder. The zippered pockets are both quite large, but neither includes any organizational pockets or compartmentalization. Its kind of a free-for-all, but theres plenty of space for a packable rain or wind jacket, extra layer, gloves, arm warmers, etc. I found the bottom zippered pocket to be my preferred spot for storing my tools and flat repair items.Moving to the front, each side of the chest has three drop-in pockets and one zippered pocket. The innermost chest pocket is made specifically to fit the soft flasks. The next two are even deeper, with lots of room for snacks, wrappers, spare gloves, you name it. Lastly, the zippered pocket finishes the pocket stack and is ideal for phones or anything else you want secured behind a zipper. Its a lot of pockets on top of each other, more than I found useful anyway, but theres no shortage of places to put your gear.Curiously, there are zippered mesh pockets on the top of each shoulder, and I dont have the slightest clue what they are for.Using the USWE Vest VSTThe USWE Vest VST is quite lightweight at 253 grams for the pack (large), plus 189 grams for the water bladder and sleeve. With its light materials, it has almost no structure when its off the body. When holding it with a full water bladder and some gear inside, its kinda like a floppy bag. That changes very quickly when you pull it on, as its vest-like fit easily conforms to the body, and it takes on a much more streamlined shape.Wearing the VST with a full 2L hydration bladder, all of my riding tools, plus a phone and snacks. In my experience, the VST is more vest-like than any of the other hydration vests Ive tried. It makes more contact with the body, and its snug, body-hugging shape results in very impressive stability, both while trail running and mountain biking. Ive used it for 6- to 10-mile trail runs and 20- to 30-mile bike rides, and it always just stays put. My only real complaint is that while running, I could hear/feel the water sloshing around in the water bladder, but thats fairly standard for running with a bladder. There isnt a dedicated clip for the hydration hose, but Ive found the small elastic loops in the chest pockets to do the trick. I have not used it with the soft flasks, so I cant comment on how that works.With the pockets on the back and the chest, theres more than enough storage for my needs. I can easily fit a light jacket, snacks, tools, flat repair, and my phone with plenty of room to spare. The pack stretches to fit bulkier items like my jacket and it doesnt get round/unstable on the back the way some other packs can when packed full then returns to its sleeker shape when the jacket is removed. Ive already touched what seems like an excess of pockets on the chest, but again, no shortage of options.Its the multiple layers of chest pockets that make some of them feel kinda redundant to me.With jacketNo jacketThe pockets stretch easily to accomodate cargo and the pack slims back down with crago removed.Its worth mentioning that even though the zippered chest pockets are super deep, your phone can fall out of there if they arent zipped. I found this out the hard way at the bottom of a 2,000-foot descent, when I did not notice that my phone popped out of an accidentally unzipped pocket, and I ran it over with my rear wheel on the first turn of the trail.Finding it was a good excuse to do a second lapMy TakeawayIf youre the type of cyclist who enjoys the occasional trail run, or vice versa, the USWE Vest VST could be the ideal pack to cover your hydration needs for both applications. If you purchase both the bladder and the soft flasks, its kinda like having two packs in one. If youre a single-sport athlete, this is still one of the best vest-style hydration packs that Ive tried and a great option for activities that require stable, distraction-free hydration and storage.The main storage is a bit of a free-for-all, but it easily accommodates extra layers and gear for long days on the bike, while the numerous front pockets keep snacks, phones, and smaller items accessible on the move. With five sizes, it should be easy for most folks to find a snug, secure fit. Just be sure to check the size chart and take some measurements, or go try one on before purchasing.The Vest VST is comfortable, breathable, lightweight, streamlined, and very stable. At $135 for the vest alone, $189 for the Bike VST setup including the bladder (or vest plus soft flasks), it doesnt come cheap, but I think its a great hydration vest for cyclists and/or runners, and potentially the perfect quiver of one for multi-sport athletes.uswe.com