Love the Platypus Big Zip SL Hydration System.

In today's box on my porch!

Platypus Big Zip SL Hydration System

I love looking out front of our house and seeing a box on the porch.  Today's box included a battery powered razor (to test for Jamboree), 2 more pair of Exofficio Men's Give-N-Go Boxer Briefs (definitely for Jamboree) and the star attraction is the Platypus Big Zip SL 1.8 liter hydration system.  I wanted a smaller system to fit in my REI Flash 18 pack (love it) and to fit in my REI Flash 22 pack which ought to hit my porch in a day or two.  The 3.0L is way too tall and takes up too much volume for the little day pack.  I love using the 3.0 L in the full backpacks.  (Platypus does also sell a 2.0L version, but the bag is the same size as the 3.0 L.

You are going to love the large
opening and easy to use big blue clip

I have used a Platypus Big Zip 3.0 Liter system for over a year (possibly two) and absolutely love it. The other bladder(s) I had in the past suffered from one or more of the following maladies:  the mouth valve leaked, some did not have a turn off setting and still leaked, the flow was so hard I was working to suck water in, the hose did not detach, and my biggest peve is they were difficult for my old fingers to open or were hard to fill.

The 1.8 L is 7.5 x 13 inches and weighs 4.0 oz.
The 3.0 L is 18.75 x 7.75 inches and weighs 5.8 oz.

None of that is true with the Big Zip.  Filling it is a breeze with the top clip sliding off, the zip-lock bag like opening easily open and spread leading to few spills and messes.  It locks by first zipping the bag and reapplying the big blue clip (which is tied on so you don't drop it in the mud while you are filling up).  The printed instruction on the bag says "slide shut to secure, invert to test."  Testing is a great idea. I have never experienced a leak under that blue clip.

Older 3.0L bite valve on the left and
new 1.8L bite valve on the right

The hose detaches with only a drop or two of leak, if that.  Once detached there is no leaking. Detaching helps thread the hose through the pack hydration port and means you do not have to pull out the hose to pull the bag out and fill it up.  the hoses are identical in length between the 1.8 L and 3.0 L systems.

Once difference seems to be the bite valve is redesigned.  Gone are the ON and OFF words and a plastic stop keeps you from rotating it the wrong way.  (The new bite valve is on the right of the older one)  I expect the bite valve will be as comfortable on the new as it is on the old one.  You can't go wrong with this system.  Buy it here at REI or check out our store for each model available via Amazon. 

You can get a cleaning kit here.
Steve