Arc'teryx Alpha FL 20 Pack
This Arc'teryx pack uses Hadron® AC2 LCP grid fabric for outstanding durability and weather resistance with very little weight. It's sized for minimalist climbs and summit pushes.
- Proprietary Hadron LCP (Liquid Crystal Polymer) grid fabric is incredibly light and exceptionally durable
- 315-denier Hadron® AC2 nylon with Hadron® is light, ultradurable and waterproof
- Lightly padded shoulder straps and a laminated back panel improve carrying comfort
- Weather resistant, lightweight, and durable
- RECCO® reflector aids search and rescue in emergency situations
- Contains materials that meet the bluesign® criteria
- PFAS (per- and polyfluoroalkyl substances) compliant
- 6 integrated front lash points let you customize external carry
- Dual dog-bone tool attachments
- Top strap secures a rope
- Bungee system compresses load and can carry crampons, ice tools or a belay parka
- Extension skirt expands capacity
- Glove-friendly drawcord main compartment with webbing pull tabs for quick and easy access
- Internal security pocket
- External WaterTight™ zippered pocket with key clip
- Thermoformed back panel provides support, structure and a comfortable carry
- Lightly padded thermoformed shoulder straps are durable, light and comfortable
Imported.
View all Arc'teryx Climbing Packs| Best Use | Climbing |
|---|---|
| Bag Style | Backpack |
| Frame Type | Internal Frame |
| Ultralight | Yes |
| Gear Capacity (L) | 24 liters |
| Gear Capacity (cu. in.) | 1,465 cubic inches |
| Hipbelt | Yes |
| Fits Torso Length (in.) | 18-20 inches |
| Fits Waist/Hips | 26-46 inches |
| Material(s) | 315d CORDURA nylon 6,6 w/4mm 400d untwisted Vectran grid, 240 gsm - 86% nylon, 14% polyarylate; 70d nylon 6 ripstop - 100% Nylon; 100d SD CORDURA nylon 6,6 Dobby, DWR FC0, 120 gsm - 100% Nylon |
| Pack Access | Top cinch |
| Number of Exterior Pockets | 1 |
| Dimensions | 22.4 x 10.6 x 7.1 inches |
| Gender | Unisex |
| Weight | 1 lb. 5.2 oz. |
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Not "water tight" at all
I really wanted to like it this pack. And it's disappointing, reaching out to Arc'teryx, which makes many products I love, justify this pack while ignoring my comments pointing out leakage in light drizzle/sleet/snow while they focus on heavy precipitation. The pack: great size, light weight, and the outer fabric seems durable. Two improvements would be making the zippers actually water tight and having a removable waist belt. Used for the 1st time on a trip in Oct where I encountered very light rain and light snow/sleet. The external pocket according to the website says "External WaterTight™ zippered pocket". I had items in this pocket including phone and tissues that got wet. On a 2nd day, in the same conditions, I purposely put tissues in the top of this pocket which all got damp again. I did this as a test so that I could be 100% sure I zipped the pocket all the way. Nothing got wet in the internal zip pocket, however, based on the bag design with only a drawcord and no external roll top I'm not sure the internal pocket would keep items dry if there was heavy precipitation and the collar filled up with water. You definitely cannot count on your gear staying dry in even light precipitation! These were the customer support responses to the issue: "While the fabric on your backpack is waterproof, water penetration will always be a small possibility under certain circumstances on any zipper. Our zippers pass rigorous tests to meet their standards of extreme wet weather, but for instance, if there is water pooling up on the zipper teeth, there will be some moisture that seeps through. To add some extra context, there are no completely waterproof zippers on the general outdoorwear market today (except on specialized dry suit products, however, they are very heavy and are stiff/difficult to operate)." A response from their website: "Hello, thank you for taking the time to share your experience. We understand how disappointing it can be when gear doesn’t perform as expected, especially in wet conditions. While we’re sorry to hear you’re unhappy with the outcome, we’d like to clarify a common misconception around the term “WaterTight™.” As noted in the product description, this backpack is weather-resistant, not waterproof, and the zippers are designed to be water-resistant, not fully waterproof. WaterTight™ zippers typically feature a coating like Polyurethane or DWR (Durable Water Repellent) that helps shed moisture. They’re built to resist light rain, splashes, or brief exposure, but they aren’t sealed tightly enough to block water under pressure or prolonged contact. We appreciate your feedback on the design and understand your concerns about the waist belt and internal protection. Your insights help us continue to refine our gear and improve how we communicate its intended use. If you have any questions about alternative packs or gear better suited for heavy rain, we’d be happy to help."

