Thanks for the responses! I checked his bike and he's got two water bottle holders so I think I'll get him one Camelback Podium Ice and one Polar, that way he can see which one he likes better and also have two so he can freeze one and put water and ice cubes in the other. I also loved the practical tips about wrapping the bottles in foil or putting them in wet socks. I'll have him try that as well.