I'm with AKSAR, after trying various Camelbak type water bladders/packs, I still use water bottles regardless of the activity as I find them a lot more versatile and also find that I use less water as they are not as convenient to sip out as compared to a Camelbak.
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Earth and sky, woods and fields, lakes and rivers, the mountain and the sea, are excellent schoolmasters, and teach some of us more than we can ever learn from books.

John Lubbock