Finally! No more frozen water. I've seen countless friends who have one of these awesome bottle holders and always thought they were too bulky and kind of pointless. Then I decided after too many frozen nalgenes to pick one up for myself, it is bulky yes... but its incredibly light weight and keeps your beverages liquid. I've only tested in cold weather but it performed well. I recommend it! Just make sure you get the right one to fit your bottle, its written in the notes.