For winter against by providing a backpack with the pipe passes in the slip otherwise the liquid will freeze and you can not drink!
For summer, glued packs freeze it remains very fresh in the backpack.
Of the two models, I did not notice any unpleasant taste like.
Well washed after each use, no problem.
Robust, really waterproof, ultra-convenient (no more having to exit the bag gourd): a must have.
