It was 108F/42C in Portland last year when I rode through on my way to WFO, and the tubing on my Skyway hydration setup had failed miserably. I stopped at the REI in Tualatin and picked up one of these, then went to a nearby Home Depot for some connectors.
This kit works great. The insulation helps, but if it's really hot and you don't take a sip every 10 minutes or so you'll still have to blow the water back out of the tube, or wind up with warm-to-hot water for the first few ounces.
The best part, in practice, is the integrated cover. It's easy (enough) to uncover and recover the bite valve one-handed, and it pretty much keeps the in-your-mouth part clean and dust free -- which isn't always easy on the road.
