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  • Ultimate Direction Fastpacks 25, 35 & 45

Related Items

Fastpack 25

Out Of Stock
You can run with this, hike, bike, or ski...boundaries don't matter with the Fastpack 25.

Specs & Details

  • Large front storage for water, phone, maps, glasses, or food
  • Sliding rail sternum straps
  • Trekking pole loops
  • Waterproof zipper
  • MonoRip Mesh is very strong, but extremely breathable
  • Patented lnfiKnit mesh is an entirely seamless back-panel and shoulder-strap system to prevent abrasion and discomfort
  • Daisy chains for securing extra gear
  • Two large side pockets for larger water vessels 

Sizing at Chest (Unisex):

  • S/M: 64 cm - 102 cm
  • M/L: 76 cm - 122 cm
  • Measure wearing the clothes you intend to wear
  • A pack full of gear will fit smaller
  • Unisex Sizing - Please confirm your bottom ribs measurement before ordering


  • Secured Volume: 24L / 1465 in3
  • Unsecured Volume: 5.2L / 317 in3
  • Total Volume: 29.2L / 1782 in3
  • Weight: 19.43 oz / 555g
  • Dimensions: 27.6" x 11" x 8.3" / 70 cm x 28 cm x 21 cm


  • MonoRip Mesh
  • 100D Robic Triple-Ripstop
  • Power Net Mesh
  • Product Reviews


    Write A Review

    1. Ben shouldn't skip chest day.

      Great pack. If the small isn't fitting you, do some pushups and pull-ups. on Apr 19th 2018

    2. Too large

      I got the S/M sized pack and it's too large on my chest. I'm a 5'7'', 145 lbs male. So, I'm small, but not even close to the smallest size UD should be considering. It's particularly large on my upper chest. The upper sternum strap is cinched all the way down and it's still loose.

      I sewed the straps between the bottle pockets and the backpack to be about 2 inches shorter and now the pack fits perfectly.

      Besides needing to be modified to fit me, this is the best pack I've ever owned. I really love it now that it fits!
      on Feb 18th 2018

    3. Versatile

      A fantastic and versatile pack. I've used the Fastpack 25 for shortish hikes, for longer ones and even for a trail run where it handled very well. I'm planning on using it for a one-night fast-pack when it warms up. Honestly, I couldn't be happier and continue to be impressed by UD's suite of awesome packs. on Jan 4th 2018

    4. Did the job but hard to run in

      Bought this for a 46 mile fast pack trip summer 2017. It was light, held what I needed, and comfortable for hiking but for some reason (not sure if I loaded it wrong or too heavy?) running with it was not ideal. Main issue being the top aspect of the pack would bounce against my upper back even when everything was cinched down tight. Overall though it got me through the adventure and I will continue to use it. on Dec 6th 2017

    5. Great for run commuting

      I use this pack for run commuting and it’s great. It does bounce a little but so do most other packs when they are loaded with around 10 - 12 pounds. I love the convenience of the up front pockets. The zippered pocket on the left side fits my iPhone 7 perfectly even with a slim case on it. I can keep my sunglasses in one of the up front bottle pockets and still use the other bottle pocket for water. Some slightly longer chest straps would be nice as well as a way to tighten the pack up on the top of my shoulders. Overall I’m really happy with it. I’m 5’11” 200lbs and the Medium Large fits just fine. on Nov 17th 2017