Do you have a metal water bottle when you exercise?

Yes I have one but I prefer in the heat of the summer to bring a Ziploc bag full of ice cubes to rub over my forearm to cool down and then drink the melted water on my return walk home. It really helps.

and all this time I thought the holder was for a can of pringles

No. I use a plastic water bottle or a camel bag when running.