Which thermos flask will be good for preparing bb milk formula? where can it be brought as well?

A couple of my friends are using the Tiger brand thermo flasks. Think it can keep the water hot/warm for up till 10 hours or so. Another friend recommended Zojirushi. She bought this brand and it is capable of keeping water hot/warm overnight. You should be able to find it at any departmental stores. For Zojirushi, it is also available on this site: http://www.momorice.com/product-category/thermo-flask/