No overflow / Straw

The pressure inside the package is larger than the outside air pressure,when we stick a straw into the drink the liquid is easily pushed out,which will dirty our clothes or table.Besides, when you pinch the soft packageby accident may also cause that state.Therefore,we will make wider the lower half of the straw than the upper part by gradient shape,which makes the straw hole bigger and the air can flow through it.Once the pressure is balanced,the liquid will not be easily pushed out.Thus you can really enjoy drinking.