Not currently available at any of our online partners
Complete the System
Add Item To Wishlist.


Osprey’s Hydraulics™ LT 1.5L Reservoir by Hydrapak® is made for light and fast activities where weight and balance are critical. Twin-welded chevron baffles stabilize the water and maintain a flat profile. The streamlined design allows for easy loading into internal hydration sleeves. Thoughtful design makes filling, cleaning and most importantly staying hydrated on the trail easier than ever. All parts are BPA-free, phthalate-free, lead-free, guaranteed. All materials are certified food safe according to FDA and EU regulations.


  • Twin Baffles - Twin-welded chevron baffles stabilize the water and maintain a flat profile.
  • Slide-Seal™ - Easy Slide-Seal™ top opening, seals watertight and provides wide access for easy filling and cleaning
  • Pour Shield - Pour shield extends the collar to ease filling in shallower sinks and control pouring into pots or bottles
  • Carry Handle - Carry handle allows easy reservoir management and filling
  • Magnetic Bite Valve - Magnet clip attaches to the reservoir hose and pairs with the included sternum strap magnet for easy water access and hose management
  • Hydrapak® Blaster™ - Hydrapak® Blaster™ bite valve offers fast, smooth water flow with a ¼ twist on/off switch
  • QuickConnect™ System - The QuickConnect™ system allows easy removal/filling of the reservoir and filtering in the backcountry


  Volume Dimensions Weight
O/S 51 in3 / 1.5 l 12.5h x 8w x 2d in. 0.35 lbs.
O/S 51 in3 / 1.5 l 32h x 19w x 4d cm 0.16 kg
TPU film
TPU film
TPU film
Product Manual Additional languages available here �
Hydraulics™ Reservoir Product Tour


Perfect for trail running


I got this pack specifically for trail runs, and after trying it out this past weekend, I am very pleased. The slim profile is the perfect size for me and I wouldn't want any more volume on a run. I like the reservoir opening, though I understand previous reviewers' concerns about drying and cleaning. It just takes a little creativity to figure out how to prop the opening wide enough for air flow. I laughed when I saw others having the same experience trying to figure out how to open it the first time. It took about 6 seconds of googling to sort it out, though, so not sure why the negativity. Overall, I love it.

SW Ohio


Well built and sturdy bladder


I use this for Day Hikes both urban and cross country. I bought it to do in the Osprey Daylight pack. It fits great in the pack. The other comments about the opening are valid, but without instructions it wasn't too difficult to figure out. In fact I think the opening is well made and I think is a plus. As for drying...took a cardboard tube from some gift wrapping paper and stuck in and it opening the bladder all the way to the bottom and allowed excellent airflow for drying. Yeah, it's rubber and there is an initial "taste"...you should always rinse/clean gear before use. The lemon in a good tip and works well. While I think most of the features of this bladder are easy to figure out it never hurts to have some simple instructions in the packaging. This works well for my uses.



Good features except trying to dry the pack


As others have mentioned, the initial opening makes you feel like you are going to rip the bladder as it almost feels like it has been glued shut. Once open it's easy enough to fill and being able to disconnect the various parts of the hose, it's easy to get in and out of your backpack. I still heard a lot of sloshing going on, but I was using it with my Osprey Rev 6 pack and didn't notice the sloshing. The drying is my biggest concern - you can use the slide from the top to keep some of the bladder open, but the end of the bladder sticks to itself. After leaving the pack airing as best I could for a couple of days, it was still wet at the bottom and looks like something was starting to grow. I then pushed a small plastic cup between the baffles which allowed it to dry, but will need to get a brush to get out the yellow stuff that grew. I only used water and this was my first use so pretty disappointing. If it had come with something to easily keep the pack open for drying I would recommend it, but without that I don't think I can recommend this as I can see 'funky stuff' growing being a real problem.

Melbourne, Australia


Include a Bite Valve Cover


This is my first Hydration Bladder. I bought (2) 1.5L from Osprey because of the quality and reputation of the company. I have used them once on a weekend backpack trip. So far, I have no complaints about the Bladder itself. My only complaint is the Bladder did not include a Bite Valve Cover. I have to pay extra for something I think should be a standard part of the Bladder. The uncovered Bite Valve can get pretty dirty during the course of a trip. Come on Osprey. $6 for a cover?? Only 4 Stars since it didn't include cover.



How Do I Get Water in It?


Please consider including a short and concise written description with diagrams on how to open the bladder to fill it with water! I got the slider thing off but had no clue how to open the bladder after that. I was afraid I was going to rip it open so I didn't want to start pulling on things. Luckily, there was another reviewer who had the same issues and took the time to describe how to open it to fill it.

Pacific NW


Initial Use Review


PROS: Lightweight Quick disconnect Very Flat Profile that is soft on all sides Very leak resistant Nice cap with magnetic strap catch Opening is a breeze once figured out CONS: Lid will not stay open on its own (difficult to clean and dry out, slightly harder to fill) Not intuitive to use on first try and has no instructions Bad taste initially that requires user to fix I like the innovative features of this pack, but the initial operation was not intuitive and there were no instructions. The first time you use it you literally think you might break the thing, but this is normal. It would help 10X to have some sort of basic instructions on the packaging, sure every feature is labelled on the back, but the names of the features do not describe each operation effectively on their own. Another issue with this pack is the bad taste on the first use. I tried running vinegar through it with hot water and soaking but could not get the taste out. After looking a little further I found that Osprey recommends lemon. This seems like an odd initial operating procedure for a new pack. It's like "hey buy this new pack, but we know it has a weird taste, and we didn't fix it before we sent it out, so you should put lemon juice in it". And my last issue with this pack is that it is hard to dry and clean. The lid by design is eager to close on itself, so when you hang it upside down it semi shuts and keeps moisture in. This means that it is constantly closing as you try to fill, dry, and clean it. Not really that bad to be honest, but it is a inconvenience and I'm worried I won't be able to dry it effectively. Rating: 5 stars for innovation and build, 2 stars for weird quirks, 4 stars overall because I respect what they have done with these packs, but think they need just some slight tweaks to educate better on operation and cleaning. I know this info is on YouTube, but I don't think it mentions any of this on the packaging.

Mountains, NC


Welded baffles prevent proper drying and cleaning


The welded baffles mean you can't turn this bladder inside out to properly dry and clean the inside. Not being able to clean it thoroughly means that you can't really put anything besides water in it (vice an electrolyte mix), lest the sugars prompt bacteria and mold growth. This bladder came in my Rev 1.5; otherwise, I never would have bought it. There are tons of other, more practical hydration bladders out there, so I suggest you find one more thoughtfully designed.

Fairfax, VA


Solidly built


Not that difficult to figure out how to use, but it's the same quality material that Osprey has always used. Except in a slimmer and lighter profile. Now there's literally zero competition between a waterbladder and a nalgene for me.

Vancouver, Canada.


No instructions provided for New season bladder


Hey Osprey - new bladder style - how about instructions - or a video. The top grey piece of plastic slides off (like on a paper presentation folder). Then unfold the piece of clear plastic - easy Now the piece that you may not be confident about - 1 inch below the top of the unfolded plastic is a second strip of plastic - pull this away from the taller piece of plastic to make the opening. This is not obvious because it is so sticky that you feel like you may be unglueing something. I am sure that it will be a great bladder - however the pack I bought it with, the Rev 1.5, is actually designed for the old style bladder making the design of the pack to accommodate the old style bladder now somewhat redundant.

Brisbane, Australia

Don't know how to loading water !!!!!!!


Without any direction for how to loading water !!!!!!!!!!!!!!!

Arlington VA


3.1 10


Notify Me