These old fashioned bottles hold their heat for a long time. You can also fill one with 50% water and 50% rubbing alcohol, and throw in the freezer. It will not freeze, but makes the best "ice pack" around. If you are unable to get rubbing alcohol, try some peppermint schnapps...but don't be surprised if your water bottle contents "evaporate" ( just kidding about the schnapps!) Also you wouldn't want a little one getting into the rubbing alcohol, so you may consider super gluing the screw top.
I have a pair....one for hot, and one for cold.
Also, makes great housewarming or get well gift!
I will be adding 2 more patterns for the e-book!!