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Fluid™ 18 Backpack


http://www.mountainhardwear.com/fluid-18-backpack-OU5948.html OU5948


Multi-use pack that's ideal for day hikers or fast-moving endurance athletes. The low-profile design offers maximum range of motion while keeping essentials within reach. Includes an easy access hydration sleeve with convenient tube exits that you can route high or low, left or right.
$64.90 $90.00
Style# 1539921
product.components.activity: Running / Training, Backpacking / Hiking


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Features & Specs

  • Weight: - 1 lb. 2 oz. / 500 g. -
  • Reviewers rated this product: - True to Size -
  • Pack Capacity: - 1100 cu. in. / 18 L -
  • Good For: - Running / Training -
  • Good For: - Backpacking / Hiking -


Multi-use pack that's ideal for day hikers or fast-moving endurance athletes. The low-profile design offers maximum range of motion while keeping essentials within reach. Includes an easy access hydration sleeve with convenient tube exits that you can route high or low, left or right.



  • Fabric Accent: Power Mesh
  • Fabric Body: 100D HT Ripstop Dobby Nylon


  • Apparel Fit: Equipment
  • Pack Weight Regular: 1 lb. 2 oz. / 500 g.
  • Pack Capacity Regular: 1100 cu. in. / 18 L
  • Pack Dim Regular: 18 in x 11 in x 9 in / 46 cm x 27 cm x 22 cm
  • Pack Torso Regular: 16.0 in. - 22.0 in. / 41 cm - 56 cm
  • Pack Waist Regular: 25 in - 37 in / 64 cm - 94 cm


  • Stash pocket on front of pack keeps jacket or other items close at hand
  • Soft, ventilated shoulder straps with integrated pockets for easy-access storage
  • Close fitting suspension with on-the-fly compression and venting channels to prevent overheating
  • Easy access hydration sleeve offers choice of routing tube over the shoulder or from lower pack, left or right
  • Zippered security pocket and key clip in protected area above shoulder straps
  • Top fleece-lined zippered pocket for safe storage of sunglasses, smart phone or other valuables
  • Stowable webbing belt adds stability when needed
  • Two deep side pockets for water bottles or other gear
  • Stowable carry loops for ice axes or trekking poles
  • High visibility, safety reflective hits
  • Imported


Fluid™ 18 Backpack is rated 4.5 out of 5 by 8.
Rated 4 out of 5 by from Almost Perfect I bought the "cyber green" version of this pack to use as a small day pack, and overall I'm very pleased. It's a great size for a pack with no frame, and has a lightweight suspension system that works well. 18L is plenty of volume for day hikes, allowing you to carry an extra layer or two, food, water, and some other small essentials. The side pockets are perfect for water bottles, I'm glad to see more and more packs moving in the "stretch/mesh" direction for side pockets. The only two things I don't like about the pack are the stash pocket on the front and the cyber green color. The stash pocket is a great idea, but the opening is small and that makes it hard to use. I'd like to see the opening made bigger. Also, it's padded, which is not needed - I think it should be made out of the same material used for the side pockets. This would save weight and bulk, and make it a true "stash" pocket.
Date published: 2016-08-17
Rated 4 out of 5 by from Quite nice This pack just fits well. Truly worn rather than carried. Holds two 1L water bottles like a dream. I slip a sit pad in the bladder compartment for added cush. The outer shovel pocket is kinda dumb though- hard to use even with my smallish hands. And why is the shovel pocket padded? A medium-sized outer zipper pocket would be more useable. In the end I can't part with this pack due to its comfort and ability to carry water bottles so well.
Date published: 2016-05-15
Rated 5 out of 5 by from Great day bag I bought this bag for an upcoming trip to Europe (only 2 days to go!). The intent was to have a day bag that was in that goldilocks zone, not too small but not too big. Something I could wear around town but also stuff in my luggage when moving place to place (mountain hardware cronus is my main backpack for trip). This bag is perfect for that. It's big enough to hold an extra layer or two, extremely light, has several pockets, and is comfortable on my back. I especially like the hidden pocket on the back top of the bag. It will be useful for stashing extra cash, card, etc and it's pretty hard to spot. I didn't even notice it for a few minutes. It actually fits in the laptop sleeve zip up back pocket of my cronus. I will be testing the water feature of the bag this summer on shorter trips and hikes/walks with the family. The water bottle pockets are still nice to have in case you don't want to use the water bladder for the day. A lot of smaller day packs I saw don't have water bottle pockets anymore. The housing for the water bladder is well thought out, and doesn't take away from any storage for the bag. I recommend this bag.
Date published: 2016-03-17
Rated 5 out of 5 by from Durable I bought this pack almost 3 years ago for a trip to Europe. I have continued to use it on a daily basis since then and it is still just as solid today as the day I bought it.
Date published: 2016-01-09
Rated 5 out of 5 by from Awesome I got this for my fiancé for Christmas, Although I was expecting it to be a bit bigger he absolutely loves it! He immediately stuffed it as full as he could with as much as he could and is super excited to take it out on day hikes/snowboarding trips. But for now it hasn't left his side since Christmas.
Date published: 2016-01-06
Rated 4 out of 5 by from Missed it by this much Nice small pack that expands like a balloon. It just needs a deeper zipper pocket on top, another zipper pocket inside, and wider shoulder straps. These additions wouldn't add much weight and would make a good pack, great.
Date published: 2015-10-02
Rated 5 out of 5 by from Great for day trips This day pack is well built and just the right size for a day pack. I'm 6'2" and it's a little small for my frame, but still works. If your 6' or shorter it will likely fit great. It's light weight and hugs your back tight. I find myself reaching for this pack most days that I only need a few items.
Date published: 2014-11-28
Rated 4 out of 5 by from Great for any length of day hike I purchased the Fluid 18. It is made from very lightweight materials, but still durable. Easily fits a 100oz bladder. I tend to overpack. This pack allows me to bring what I actually need and all the junk I don't. Opens up for easy packing. Cinches down nicely so your pack isn't flopping around.
Date published: 2014-11-22
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