Insulated stainless-steel tumbler with a completely leak-proof lid

SmoothSip Slider spout offers an ultra-comfortable sip every time

Slide-top spout design prevents splashes or spills

Double-wall insulation keeps drinks hot for 6 hours and cold for up to 24 hours

BPA and phthalate-free. Hand wash cup, dishwasher-safe lid

      The vacuum thermos flask is also called a thermos flask or a thermos flask. Its thermal insulation principle is achieved by utilizing the vacuum layer between the two walls of the bottle. The vacuum layer works by creating a vacuum, which means there is no air or gas between the inner and outer walls of the flask. Since air is a good conductor of heat, a lack of air minimizes heat transfer by conduction and convection. This prevents the contents of the flask from losing heat to the surrounding environment or gaining heat. In addition, the inner and outer walls of the flask are generally made of stainless steel, which is a poor conductor of heat. This helps to further reduce heat transfer since stainless steel has a lower thermal conductivity. The vacuum layer and the flask's stainless steel walls together effectively trap heat, keeping the contents hot or cold for longer. This makes vacuum flasks a popular choice for keeping drinks at the desired temperature while on the go.