This small hole is a vent, which uses physical means to reduce the pressure difference inside the bottle and help you open the bottle more conveniently. Therefore, during the pouring process, if the straw is open, there will be a slight possibility of water dripping from the small air hole. This is a normal phenomenon. There will be no dripping when the straw is closed.

Product Name: Creative Insulation Cup

Features: Double layer, anti-scald

Material: 304 stainless steel

Color: Red, Gold, Blue,Green

Capacity: 350ML/500ml

Package List: Water bottle * 1

Creative Thermos Coke Shape 350/500ML Travel Student Cup Office Car Kettle Portable Stainless Steel Straw Drinking Coffee Cup