How to choose a good thermal bottle?

When choosing thermal bottle, people will try to hear the thermal bottle. Is this a good way for choosing a good thermal bottle? In fact, you would hear sound regardless of the quality of the thermal bottle. So how to choose a good thermal bottle?

Safe: choose thermal bottles made with 304 stainless steel
Bottle surface: no scratches or dents
Easy to wash: in addition to detachable parts, the stainless steel inside is also important. Some thermal bottles are with coating, it will come off after some time. However, using polished stainless steel can make cleaning easier.

Last but not least, remember to try the bottle when you bought home. Pour in hot water and rest it for around 15 mins. If the bottle body is not hot, the bottle is performing well.