The Big Zip II has been discontinued. If you're looking for something new, check out the best hydration reservoirs for 2020.
Historic Range: $15.95-$34.95
Reviewers Paid: $15.99-$28.95
I'm currently on my second Big Zip (first one fell off of my motorcycle and when I shipped it back to Cascade Designs for repair, they replaced it for free, even though the failure was my fault) and have had excellent service from this product. The Big Zip allows the addition of ice for short, warm day trips and the design is excellent.
I have been using my Big Zip for over 7 years with no failure. Both on my motorcycle and day hiking trips. This is a great product.
Price Paid: $15.99
When I bought a sub-2-pound pack, I needed a reservoir that was lightweight and slim (tubular/cylindrical reservoirs created an uncomfortable bulge in the back of the pack). I settled on the Big Zip since it allowed me to carry a lot of water for the weight. On only the third use, the adaptor where the hose enters the reservoir cracked and developed a fast leak. Not what you want from your reservoir in the middle of your hike (good thing it was a 20 mi loop and not a multiday excursion)!
I believe the failure was the result of poor design as the bag tends to get a kink in it in the area of the tube entrance, placing pressure on the adaptor. Bottom line, this product is not durable enough to warrant ANY confidence. Be safe and take something stronger.
Price Paid: $28.95