I use one all the time. In hot weather, put ice in it, then water, then carry Gatorade or whatever in your waterbottles. A camelbak keeps stuff cooler than insulated water bottles. Buy a spare tip, put it in a baggie, throw down at the bottom, and if you ever lose the tip, you've got a spare.
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"be careful this rando stuff is addictive and dan's the 'pusher'."