Sharon wrote an answer about MSR Hydration Kit - For use with any MSR Bag on January 11, 2012
Hi...I also had a less than stellar experience with my MRS Hydration Kit a few weeks ago in northern Ontario. I was in a group of 7 hikers and everyone else had a camelback with insulated hose kit. My MSR was the only hose that froze. I thought like one of the previous posters that if I fed the hose through my backpack's shoulder strap, that it would be kept warm enough. Not the case and it was a VERY long day of cold hiking with little water... I learned my lesson... I'm moving back to my old faithful water bottle and insulated pouch....(note.. I didn't try blowing back into the hose so maybe that's the trick but honestly, I don't want to take the chance of frozen water again).